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middlemarch.eth

middlemarch.eth

3 years ago

ERC721R: A new ERC721 contract for random minting so people don’t snipe all the rares!

That is, how to snipe all the rares without using ERC721R!

Introduction: Blessed and Lucky 

Mphers was the first mfers derivative, and as a Phunks derivative, I wanted one.

I wanted an alien. And there are only 8 in the 6,969 collection. I got one!

In case it wasn't clear from the tweet, I meant that I was lucky to have figured out how to 100% guarantee I'd get an alien without any extra luck.
Read on to find out how I did it, how you can too, and how developers can avoid it!
How to make rare NFTs without luck.

# How to mint rare NFTs without needing luck

The key to minting a rare NFT is knowing the token's id ahead of time.

For example, once I knew my alien was #4002, I simply refreshed the mint page until #3992 was minted, and then mint 10 mphers.

How did I know #4002 was extraterrestrial? Let's go back.

First, go to the mpher contract's Etherscan page and look up the tokenURI of a previously issued token, token #1:

As you can see, mphers creates metadata URIs by combining the token id and an IPFS hash.

This method gives you the collection's provenance in every URI, and while that URI can be changed, it affects everyone and is public.

Consider a token URI without a provenance hash, like https://mphers.art/api?tokenId=1.
As a collector, you couldn't be sure the devs weren't changing #1's metadata at will.
The API allows you to specify “if #4002 has not been minted, do not show any information about it”, whereas IPFS does not allow this.

It's possible to look up the metadata of any token, whether or not it's been minted.
Simply replace the trailing “1” with your desired id.


Mpher #4002

These files contain all the information about the mpher with the specified id. For my alien, we simply search all metadata files for the string “alien mpher.”

Take a look at the 6,969 meta-data files I'm using OpenSea's IPFS gateway, but you could use ipfs.io or something else.


Use curl to download ten files at once. Downloading thousands of files quickly can lead to duplicates or errors. But with a little tweaking, you should be able to get everything (and dupes are fine for our purposes).
Now that you have everything in one place, grep for aliens:


The numbers are the file names that contain “alien mpher” and thus the aliens' ids.
The entire process takes under ten minutes. This technique works on many NFTs currently minting.

In practice, manually minting at the right time to get the alien is difficult, especially when tokens mint quickly. Then write a bot to poll totalSupply() every second and submit the mint transaction at the exact right time.

You could even look for the token you need in the mempool before it is minted, and get your mint into the same block!

However, in my experience, the “big” approach wins 95% of the time—but not 100%.
“Am I being set up all along?”

Is a question you might ask yourself if you're new to this.
It's disheartening to think you had no chance of minting anything that someone else wanted.
But, did you have no opportunity? You had an equal chance as everyone else!
Take me, for instance: I figured this out using open-source tools and free public information. Anyone can do this, and not understanding how a contract works before minting will lead to much worse issues.

The mpher mint was fair.

While a fair game, “snipe the alien” may not have been everyone's cup of tea.
People may have had more fun playing the “mint lottery” where tokens were distributed at random and no one could gain an advantage over someone simply clicking the “mint” button.

How might we proceed?
Minting For Fashion Hats Punks, I wanted to create a random minting experience without sacrificing fairness. In my opinion, a predictable mint beats an unfair one. Above all, participants must be equal.

Sadly, the most common method of creating a random experience—the post-mint “reveal”—is deeply unfair. It works as follows:

  • During the mint, token metadata is unavailable. Instead, tokenURI() returns a blank JSON file for each id.
  • An IPFS hash is updated once all tokens are minted.
  • You can't tell how the contract owner chose which token ids got which metadata, so it appears random.

Because they alone decide who gets what, the person setting the metadata clearly has a huge unfair advantage over the people minting. Unlike the mpher mint, you have no chance of winning here.
But what if it's a well-known, trusted, doxxed dev team? Are reveals okay here?
No! No one should be trusted with such power. Even if someone isn't consciously trying to cheat, they have unconscious biases. They might also make a mistake and not realize it until it's too late, for example.

You should also not trust yourself. Imagine doing a reveal, thinking you did it correctly (nothing is 100%! ), and getting the rarest NFT. Isn't that a tad odd Do you think you deserve it? An NFT developer like myself would hate to be in this situation.

Reveals are bad*

UNLESS they are done without trust, meaning everyone can verify their fairness without relying on the developers (which you should never do).
An on-chain reveal powered by randomness that is verifiably outside of anyone's control is the most common way to achieve a trustless reveal (e.g., through Chainlink).

Tubby Cats did an excellent job on this reveal, and I highly recommend their contract and launch reflections. Their reveal was also cool because it was progressive—you didn't have to wait until the end of the mint to find out.

In his post-launch reflections, @DefiLlama stated that he made the contract as trustless as possible, removing as much trust as possible from the team.

In my opinion, everyone should know the rules of the game and trust that they will not be changed mid-stream, while trust minimization is critical because smart contracts were designed to reduce trust (and it makes it impossible to hack even if the team is compromised). This was a huge mistake because it limited our flexibility and our ability to correct mistakes.

And @DefiLlama is a superstar developer. Imagine how much stress maximizing trustlessness will cause you!

That leaves me with a bad solution that works in 99 percent of cases and is much easier to implement: random token assignments.

Introducing ERC721R: A fully compliant IERC721 implementation that picks token ids at random.

ERC721R implements the opposite of a reveal: we mint token ids randomly and assign metadata deterministically.
This allows us to reveal all metadata prior to minting while reducing snipe chances.
Then import the contract and use this code:

What is ERC721R and how does it work

First, a disclaimer: ERC721R isn't truly random. In this sense, it creates the same “game” as the mpher situation, where minters compete to exploit the mint. However, ERC721R is a much more difficult game.
To game ERC721R, you need to be able to predict a hash value using these inputs:

This is impossible for a normal person because it requires knowledge of the block timestamp of your mint, which you do not have.

To do this, a miner must set the timestamp to a value in the future, and whatever they do is dependent on the previous block's hash, which expires in about ten seconds when the next block is mined.

This pseudo-randomness is “good enough,” but if big money is involved, it will be gamed. Of course, the system it replaces—predictable minting—can be manipulated.
The token id is chosen in a clever implementation of the Fisher–Yates shuffle algorithm that I copied from CryptoPhunksV2.

Consider first the naive solution: (a 10,000 item collection is assumed):

  1. Make an array with 0–9999.
  2. To create a token, pick a random item from the array and use that as the token's id.
  3. Remove that value from the array and shorten it by one so that every index corresponds to an available token id.

This works, but it uses too much gas because changing an array's length and storing a large array of non-zero values is expensive.

How do we avoid them both? What if we started with a cheap 10,000-zero array? Let's assign an id to each index in that array.

Assume we pick index #6500 at random—#6500 is our token id, and we replace the 0 with a 1.

But what if we chose #6500 again? A 1 would indicate #6500 was taken, but then what? We can't just "roll again" because gas will be unpredictable and high, especially later mints.

This allows us to pick a token id 100% of the time without having to keep a separate list. Here's how it works:

  1. Make a 10,000 0 array.
  2. Create a 10,000 uint numAvailableTokens.
  3. Pick a number between 0 and numAvailableTokens. -1
  4. Think of #6500—look at index #6500. If it's 0, the next token id is #6500. If not, the value at index #6500 is your next token id (weird!)
  5. Examine the array's last value, numAvailableTokens — 1. If it's 0, move the value at #6500 to the end of the array (#9999 if it's the first token). If the array's last value is not zero, update index #6500 to store it.
  6. numAvailableTokens is decreased by 1.
  7. Repeat 3–6 for the next token id.

So there you go! The array stays the same size, but we can choose an available id reliably. The Solidity code is as follows:


GitHub url

Unfortunately, this algorithm uses more gas than the leading sequential mint solution, ERC721A.

This is most noticeable when minting multiple tokens in one transaction—a 10 token mint on ERC721R costs 5x more than on ERC721A. That said, ERC721A has been optimized much further than ERC721R so there is probably room for improvement.

Conclusion

Listed below are your options:

  • ERC721A: Minters pay lower gas but must spend time and energy devising and executing a competitive minting strategy or be comfortable with worse minting results.
  • ERC721R: Higher gas, but the easy minting strategy of just clicking the button is optimal in all but the most extreme cases. If miners game ERC721R it’s the worst of both worlds: higher gas and a ton of work to compete.
  • ERC721A + standard reveal: Low gas, but not verifiably fair. Please do not do this!
  • ERC721A + trustless reveal: The best solution if done correctly, highly-challenging for dev, potential for difficult-to-correct errors.

Did I miss something? Comment or tweet me @dumbnamenumbers.
Check out the code on GitHub to learn more! Pull requests are welcome—I'm sure I've missed many gas-saving opportunities.

Thanks!

Read the original post here

More on NFTs & Art

Yuga Labs

Yuga Labs

3 years ago

Yuga Labs (BAYC and MAYC) buys CryptoPunks and Meebits and gives them commercial rights

Yuga has acquired the CryptoPunks and Meebits NFT IP from Larva Labs. These include 423 CryptoPunks and 1711 Meebits.

We set out to create in the NFT space because we admired CryptoPunks and the founders' visionary work. A lot of their work influenced how we built BAYC and NFTs. We're proud to lead CryptoPunks and Meebits into the future as part of our broader ecosystem.

"Yuga Labs invented the modern profile picture project and are the best in the world at operating these projects. They are ideal CrytoPunk and Meebit stewards. We are confident that in their hands, these projects will thrive in the emerging decentralized web.”
–The founders of Larva Labs, CryptoPunks, and Meebits

This deal grew out of discussions between our partner Guy Oseary and the Larva Labs founders. One call led to another, and now we're here. This does not mean Matt and John will join Yuga. They'll keep running Larva Labs and creating awesome projects that help shape the future of web3.

Next steps

Here's what we plan to do with CryptoPunks and Meebits now that we own the IP. Owners of CryptoPunks and Meebits will soon receive commercial rights equal to those of BAYC and MAYC holders. Our legal teams are working on new terms and conditions for both collections, which we hope to share with the community soon. We expect a wide range of third-party developers and community creators to incorporate CryptoPunks and Meebits into their web3 projects. We'll build the brand alongside them.

We don't intend to cram these NFT collections into the BAYC club model. We see BAYC as the hub of the Yuga universe, and CryptoPunks as a historical collection. We will work to improve the CryptoPunks and Meebits collections as good stewards. We're not in a hurry. We'll consult the community before deciding what to do next.

For us, NFTs are about culture. We're deeply invested in the BAYC community, and it's inspiring to see them grow, collaborate, and innovate. We're excited to see what CryptoPunks and Meebits do with IP rights. Our goal has always been to create a community-owned brand that goes beyond NFTs, and now we can include CryptoPunks and Meebits.

Nate Kostar

3 years ago

# DeaMau5’s PIXELYNX and Beatport Launch Festival NFTs

Pixelynx, a music metaverse gaming platform, has teamed up with Beatport, an online music retailer focusing in electronic music, to establish a Synth Heads non-fungible token (NFT) Collection.

Richie Hawtin, aka Deadmau5, and Joel Zimmerman, nicknamed Pixelynx, have invented a new music metaverse game platform called Pixelynx. In January 2022, they released their first Beatport NFT drop, which saw 3,030 generative NFTs sell out in seconds.

The limited edition Synth Heads NFTs will be released in collaboration with Junction 2, the largest UK techno festival, and having one will grant fans special access tickets and experiences at the London-based festival.

Membership in the Synth Head community, day passes to the Junction 2 Festival 2022, Junction 2 and Beatport apparel, special vinyl releases, and continued access to future ticket drops are just a few of the experiences available.

Five lucky NFT holders will also receive a Golden Ticket, which includes access to a backstage artist bar and tickets to Junction 2's next large-scale London event this summer, in addition to full festival entrance for both days.

The Junction 2 festival will take place at Trent Park in London on June 18th and 19th, and will feature performances from Four Tet, Dixon, Amelie Lens, Robert Hood, and a slew of other artists. Holders of the original Synth Head NFT will be granted admission to the festival's guestlist as well as line-jumping privileges.

The new Synth Heads NFTs collection  contain 300 NFTs.

NFTs that provide IRL utility are in high demand.

The benefits of NFT drops related to In Real Life (IRL) utility aren't limited to Beatport and Pixelynx.

Coachella, a well-known music event, recently partnered with cryptocurrency exchange FTX to offer free NFTs to 2022 pass holders. Access to a dedicated entry lane, a meal and beverage pass, and limited-edition merchandise were all included with the NFTs.

Coachella also has its own NFT store on the Solana blockchain, where fans can buy Coachella NFTs and digital treasures that unlock exclusive on-site experiences, physical objects, lifetime festival passes, and "future adventures."

Individual artists and performers have begun taking advantage of NFT technology outside of large music festivals like Coachella.

DJ Tisto has revealed that he would release a VIP NFT for his upcoming "Eagle" collection during the EDC festival in Las Vegas in 2022. This NFT, dubbed "All Access Eagle," gives collectors the best chance to get NFTs from his first drop, as well as unique access to the music "Repeat It."

NFTs are one-of-a-kind digital assets that can be verified, purchased, sold, and traded on blockchains, opening up new possibilities for artists and businesses alike. Time will tell whether Beatport and Pixelynx's Synth Head NFT collection will be successful, but if it's anything like the first release, it's a safe bet.

Jayden Levitt

Jayden Levitt

3 years ago

Starbucks' NFT Project recently defeated its rivals.

The same way Amazon killed bookstores. You just can’t see it yet.

Photo by Jason Redmond | AFP | Getty Images

Shultz globalized coffee. Before Starbucks, coffee sucked.

All accounts say 1970s coffee was awful.

Starbucks had three stores selling ground Indonesian coffee in the 1980s.

What a show!

A year after joining the company at 29, Shultz traveled to Italy for R&D.

He noticed the coffee shops' sense of theater and community and realized Starbucks was in the wrong business.

Integrating coffee and destination created a sense of community in the store.

Brilliant!

He told Starbucks' founders about his experience.

They disapproved.

For two years.

Shultz left and opened an Italian coffee shop chain like any good entrepreneur.

Starbucks ran into financial trouble, so the founders offered to sell to Shultz.

Shultz bought Starbucks in 1987 for $3.8 million, including six stores and a payment plan.

Starbucks is worth $100.79Billion, per Google Finance.

26,500 times Shultz's initial investment

Starbucks is releasing its own NFT Platform under Shultz and his early Vision.

This year, Starbucks Odyssey launches. The new digital experience combines a Loyalty Rewards program with NFT.

The side chain Polygon-based platform doesn't require a Crypto Wallet. Customers can earn and buy digital assets to unlock incentives and experiences.

They've removed all friction, making it more immersive and convenient than a coffee shop.

Brilliant!

NFTs are the access coupon to their digital community, but they don't highlight the technology.

They prioritize consumer experience by adding non-technical users to Web3. Their collectables are called journey stamps, not NFTs.

No mention of bundled gas fees.

Brady Brewer, Starbucks' CMO, said;

“It happens to be built on blockchain and web3 technologies, but the customer — to be honest — may very well not even know that what they’re doing is interacting with blockchain technology. It’s just the enabler,”

Rewards members will log into a web app using their loyalty program credentials to access Starbucks Odyssey. They won't know about blockchain transactions.

Join the waitlist here

Starbucks has just dealt its rivals a devastating blow.

It generates more than ten times the revenue of its closest competitor Costa Coffee.

The coffee giant is booming.

Credit — Statista.com

Starbucks is ahead of its competitors. No wonder.

They have an innovative, adaptable leadership team.

Starbucks' DNA challenges the narrative, especially when others reject their ideas.

I’m off for a cappuccino.

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Dr. Linda Dahl

Dr. Linda Dahl

3 years ago

We eat corn in almost everything. Is It Important?

Photo by Mockup Graphics on Unsplash

Corn Kid got viral on TikTok after being interviewed by Recess Therapy. Tariq, called the Corn Kid, ate a buttery ear of corn in the video. He's corn crazy. He thinks everyone just has to try it. It turns out, whether we know it or not, we already have.

Corn is a fruit, veggie, and grain. It's the second-most-grown crop. Corn makes up 36% of U.S. exports. In the U.S., it's easy to grow and provides high yields, as proven by the vast corn belt spanning the Midwest, Great Plains, and Texas panhandle. Since 1950, the corn crop has doubled to 10 billion bushels.

You say, "Fine." We shouldn't just grow because we can. Why so much corn? What's this corn for?

Why is practical and political. Michael Pollan's The Omnivore's Dilemma has the full narrative. Early 1970s food costs increased. Nixon subsidized maize to feed the public. Monsanto genetically engineered corn seeds to make them hardier, and soon there was plenty of corn. Everyone ate. Woot! Too much corn followed. The powers-that-be had to decide what to do with leftover corn-on-the-cob.

They are fortunate that corn has a wide range of uses.

First, the edible variants. I divide corn into obvious and stealth.

Obvious corn includes popcorn, canned corn, and corn on the cob. This form isn't always digested and often comes out as entire, polka-dotting poop. Cornmeal can be ground to make cornbread, polenta, and corn tortillas. Corn provides antioxidants, minerals, and vitamins in moderation. Most synthetic Vitamin C comes from GMO maize.

Corn oil, corn starch, dextrose (a sugar), and high-fructose corn syrup are often overlooked. They're stealth corn because they sneak into practically everything. Corn oil is used for frying, baking, and in potato chips, mayonnaise, margarine, and salad dressing. Baby food, bread, cakes, antibiotics, canned vegetables, beverages, and even dairy and animal products include corn starch. Dextrose appears in almost all prepared foods, excluding those with high-fructose corn syrup. HFCS isn't as easily digested as sucrose (from cane sugar). It can also cause other ailments, which we'll discuss later.

Most foods contain corn. It's fed to almost all food animals. 96% of U.S. animal feed is corn. 39% of U.S. corn is fed to livestock. But animals prefer other foods. Omnivore chickens prefer insects, worms, grains, and grasses. Captive cows are fed a total mixed ration, which contains corn. These animals' products, like eggs and milk, are also corn-fed.

There are numerous non-edible by-products of corn that are employed in the production of items like:

  1. fuel-grade ethanol

  2. plastics

  3. batteries

  4. cosmetics

  5. meds/vitamins binder

  6. carpets, fabrics

  7. glutathione

  8. crayons

  9. Paint/glue

How does corn influence you? Consider quick food for dinner. You order a cheeseburger, fries, and big Coke at the counter (or drive-through in the suburbs). You tell yourself, "No corn." All that contains corn. Deconstruct:

Cows fed corn produce meat and cheese. Meat and cheese were bonded with corn syrup and starch (same). The bun (corn flour and dextrose) and fries were fried in maize oil. High fructose corn syrup sweetens the drink and helps make the cup and straw.

Just about everything contains corn. Then what? A cornspiracy, perhaps? Is eating too much maize an issue, or should we strive to stay away from it whenever possible?

As I've said, eating some maize can be healthy. 92% of U.S. corn is genetically modified, according to the Center for Food Safety. The adjustments are expected to boost corn yields. Some sweet corn is genetically modified to produce its own insecticide, a protein deadly to insects made by Bacillus thuringiensis. It's safe to eat in sweet corn. Concerns exist about feeding agricultural animals so much maize, modified or not.

High fructose corn syrup should be consumed in moderation. Fructose, a sugar, isn't easily metabolized. Fructose causes diabetes, fatty liver, obesity, and heart disease. It causes inflammation, which might aggravate gout. Candy, packaged sweets, soda, fast food, juice drinks, ice cream, ice cream topping syrups, sauces & condiments, jams, bread, crackers, and pancake syrup contain the most high fructose corn syrup. Everyday foods with little nutrients. Check labels and choose cane sugar or sucrose-sweetened goods. Or, eat corn like the Corn Kid.

Hunter Walk

Hunter Walk

2 years ago

Is it bad of me to want our portfolio companies to generate greater returns for outside investors than they did for us as venture capitalists?

Wishing for Lasting Companies, Not Penny Stocks or Goodwill Write-Downs

Get me a NASCAR-style company-logoed cremation urn (notice to the executor of my will, theres gonna be a lot of weird requests). I believe in working on projects that would be on your tombstone. As the Homebrew logo is tattooed on my shoulder, expanding the portfolio to my posthumous commemoration is easy. But this isn't an IRR victory lap; it's a hope that the firms we worked for would last beyond my lifetime.

a little boy planting a dollar bill in the ground and pouring a watering can out on it, digital art [DALL-E]

Venture investors too often take credit or distance themselves from startups based on circumstances. Successful companies tell stories of crucial introductions, strategy conversations, and other value. Defeats Even whether our term involves Board service or systematic ethical violations, I'm just a little investment, so there's not much I can do. Since I'm guilty, I'm tossing stones from within the glass home (although we try to own our decisions through the lifecycle).

Post-exit company trajectories are usually unconfounded. Off the cap table, no longer a shareholder (or a diminishing one as you sell off/distribute), eventually leaving the Board. You can cheer for the squad or forget about it, but you've freed the corporation and it's back to portfolio work.

As I look at the downward track of most SPACs and other tarnished IPOs from the last few years, I wonder how I would feel if those were my legacy. Is my job done? Yes. When investing in a business, the odds are against it surviving, let alone thriving and being able to find sunlight. SPAC sponsors, institutional buyers, retail investments. Free trade in an open market is their right. Risking and losing capital is the system working! But

We were lead or co-lead investors in our first three funds, but as additional VCs joined the company, we were pushed down the cap table. Voting your shares rarely matters; supporting the firm when they need it does. Being valuable, consistent, and helping the company improve builds trust with the founders.

I hope every startup we sponsor becomes a successful public company before, during, and after we benefit. My perspective of American capitalism. Well, a stock ticker has a lot of garbage, and I support all types of regulation simplification (in addition to being a person investor in the Long-Term Stock Exchange). Yet being owned by a large group of investors and making actual gains for them is great. Likewise does seeing someone you met when they were just starting out become a public company CEO without losing their voice, leadership, or beliefs.

I'm just thinking about what we can do from the start to realize value from our investments and build companies with bright futures. Maybe seed venture financing shouldn't impact those outcomes, but I'm not comfortable giving up that obligation.

Ethan Siegel

Ethan Siegel

2 years ago

How you view the year will change after using this one-page calendar.

The conventional way we display annual calendars, at left, requires us to examine each month separately, either relegating the full year to a tiny font on a single page or onto 12 separate pages. Instead, the one-page calendar, at right, enables you to find whatever you want all throughout the year. (Credit: E. Siegel, with a public domain conventional calendar at left)

No other calendar is simpler, smaller, and reusable year after year. It works and is used here.

Most of us discard and replace our calendars annually. Each month, we move our calendar ahead another page, thus if we need to know which day of the week corresponds to a given day/month combination, we have to calculate it or flip forward/backward to the corresponding month. Questions like:

  • What day does this year's American Thanksgiving fall on?

  • Which months contain a Friday the thirteenth?

  • When is July 4th? What day of the week?

  • Alternatively, what day of the week is Christmas?

They're hard to figure out until you switch to the right month or look up all the months.

However, mathematically, the answers to these questions or any question that requires matching the day of the week with the day/month combination in a year are predictable, basic, and easy to work out. If you use this one-page calendar instead of a 12-month calendar, it lasts the whole year and is easy to alter for future years. Let me explain.

Rather than a calendar displaying separate images for each month out of the year, this one-page calendar can be used to match up the day of the week with the dates/months of the year with perfect accuracy all in a single view. (Credit: E. Siegel)

The 2023 one-page calendar is above. The days of the month are on the lower left, which works for all months if you know that:

  • There are 31 days in January, March, May, July, August, October, and December.

  • All of the months of April, June, September, and November have 30 days.

  • And depending on the year, February has either 28 days (in non-leap years) or 29 days (in leap years).

If you know this, this calendar makes it easy to match the day/month of the year to the weekday.

Here are some instances. American Thanksgiving is always on the fourth Thursday of November. You'll always know the month and day of the week, but the date—the day in November—changes each year.

On any other calendar, you'd have to flip to November to see when the fourth Thursday is. This one-page calendar only requires:

  • pick the month of November in the top-right corner to begin.

  • drag your finger down until Thursday appears,

  • then turn left and follow the monthly calendar until you reach the fourth Thursday.

To find American Thanksgiving, you need to find the 4th Thursday in November. Using the one-page calendar, start at November, move down to find Thursday, then move to the left to count off to the fourth Thursday in November. In 2023, that date will be November 23rd. (Credit: E. Siegel)

It's obvious: 2023 is the 23rd American Thanksgiving. For every month and day-of-the-week combination, start at the month, drag your finger down to the desired day, and then move to the left to see which dates match.

What if you knew the day of the week and the date of the month, but not the month(s)?

A different method using the same one-page calendar gives the answer. Which months have Friday the 13th this year? Just:

  • begin on the 13th of the month, the day you know you desire,

  • then swipe right with your finger till Friday appears.

  • and then work your way up until you can determine which months the specific Friday the 13th falls under.

If you know which date/day-of-the-week combination you’re seeking but don’t know which months will meet that criteria, start with the date (1–31), move to the right until you find the day of the week you want, then move up and find which months match that criteria. Every year will always have at least one such combination. (Credit: E. Siegel)

One Friday the 13th occurred in January 2023, and another will occur in October.

The most typical reason to consult a calendar is when you know the month/day combination but not the day of the week.

Compared to single-month calendars, the one-page calendar excels here. Take July 4th, for instance. Find the weekday here:

  • beginning on the left on the fourth of the month, as you are aware,

  • also begin with July, the month of the year you are most familiar with, at the upper right,

  • you should move your two fingers in the opposite directions till they meet: on a Tuesday in 2023.

That's how you find your selected day/month combination's weekday.

If you were curious as to which day of the week July 4th, 2023 fell on, rather than flipping a conventional calendar to July and seeing, you could trace “4” to the right and “July” down, finding where they meet (on a Tuesday) revealing the day-of-the-week. (Credit: E. Siegel)

Another example: Christmas. Christmas Day is always December 25th, however unless your conventional calendar is open to December of your particular year, a question like "what day of the week is Christmas?" difficult to answer.

Unlike the one-page calendar!

Remember the left-hand day of the month. Top-right, you see the month. Put two fingers, one from each hand, on the date (25th) and the month (December). Slide the day hand to the right and the month hand downwards until they touch.

They meet on Monday—December 25, 2023.

Using the one-page calendar for 2023, you can figure out the day-of-the-week of any calendar day by placing one finger on the “date” at left and another on the “month” at top. By moving your fingers respectively to the right and down, where they meet will reveal the day of the week to you. (Credit: E. Siegel)

For 2023, that's fine, but what happens in 2024? Even worse, what if we want to know the day-of-the-week/day/month combo many years from now?

I think the one-page calendar shines here.

Except for the blue months in the upper-right corner of the one-page calendar, everything is the same year after year. The months also change in a consistent fashion.

Each non-leap year has 365 days—one more than a full 52 weeks (which is 364). Since January 1, 2023 began on a Sunday and 2023 has 365 days, we immediately know that December 31, 2023 will conclude on a Sunday (which you can confirm using the one-page calendar) and that January 1, 2024 will begin on a Monday. Then, reorder the months for 2024, taking in mind that February will have 29 days in a leap year.

This image shows the one-page calendar view for the next leap year we’re going to experience: 2024. Note that the monthly patterns have changed from how they were in a non-leap year, displaying a new pattern unique to leap years, corresponding to the fact that February has 29 days instead of 28. (Credit: E. Siegel)

Please note the differences between 2023 and 2024 month placement. In 2023:

  • October and January began on the same day of the week.

  • On the following Monday of the week, May began.

  • August started on the next day,

  • then the next weekday marked the start of February, March, and November, respectively.

  • Unlike June, which starts the following weekday,

  • While September and December start on the following day of the week,

  • Lastly, April and July start one extra day later.

Since 2024 is a leap year, February has 29 days, disrupting the rhythm. Month placements change to:

  • The first day of the week in January, April, and July is the same.

  • October will begin the following day.

  • Possibly starting the next weekday,

  • February and August start on the next weekday,

  • beginning on the following day of the week between March and November,

  • beginning the following weekday in June,

  • and commencing one more day of the week after that, September and December.

Due to the 366-day leap year, 2025 will start two days later than 2024 on January 1st.

The non-leap year 2025 has the same calendar as 2023, expect with the days-of-the-week that each month begins on shifted forward by three days for each month. This is because 2023 was not a leap year and 2024 was, meaning that an extra 3 days are needed over and above the 104 full weeks contained in 2023 and 2024 combined. (Credit: E. Siegel)

Now, looking at the 2025 calendar, you can see that the 2023 pattern of which months start on which days is repeated! The sole variation is a shift of three days-of-the-week ahead because 2023 had one more day (365) than 52 full weeks (364), and 2024 had two more days (366). Again,

  • On Wednesday this time, January and October begin on the same day of the week.

  • Although May begins on Thursday,

  • August begins this Friday.

  • March, November, and February all begin on a Saturday.

  • Beginning on a Sunday in June

  • Beginning on Monday are September and December,

  • and on Tuesday, April and July begin.

In 2026 and 2027, the year will commence on a Thursday and a Friday, respectively.

The one-page calendars for 2026 and 2027, as shown next to one another. Note that the calendars are identical, save that the day-of-the-week that each month begins on is shifted by one day from the prior year to the next. This occurs every time a non-leap year is followed by another non-leap year. (Credit: E. Siegel)

We must return to our leap year monthly arrangement in 2028. Yes, January 1, 2028 begins on a Saturday, but February, which begins on a Tuesday three days before January, will have 29 days. Thus:

  • Start dates for January, April, and July are all Saturdays.

  • Given that October began on Sunday,

  • Although May starts on a Monday,

  • beginning on a Tuesday in February and August,

  • Beginning on a Wednesday in March and November,

  • Beginning on Thursday, June

  • and Friday marks the start of September and December.

This is great because there are only 14 calendar configurations: one for each of the seven non-leap years where January 1st begins on each of the seven days of the week, and one for each of the seven leap years where it begins on each day of the week.

This example of a one-page calendar, which represents the year 2028, will be valid for all leap years that begin with January 1st on a Saturday. The leap year version of the one-page calendar repeats every 28 years, unless you pass a non-leap year ending in “00,” in which case the repeat will either be 12 or 40 years instead. (Credit: E. Siegel)

The 2023 calendar will function in 2034, 2045, 2051, 2062, 2073, 2079, 2090, 2102, 2113, and 2119. Except when passing over a non-leap year that ends in 00, like 2100, the repeat time always extends to 12 years or shortens to an extra 6 years.

  • The pattern is repeated in 2025's calendar in 2031, 2042, 2053, 2059, 2070, 2081, 2087, 2098, 2110, and 2121.

  • The extra 6-year repeat at the end of the century on the calendar for 2026 will occur in the years 2037, 2043, 2054, 2065, 2071, 2082, 2093, 2099, 2105, and 2122.

  • The 2027s calendar repeats in 2038, 2049, 2055, 2066, 2077, 2083, 2094, 2100, 2106, and 2117, almost exactly matching the 2026s pattern.

For leap years, the recurrence pattern is every 28 years when not passing a non-leap year ending in 00, or 12 or 40 years when we do. 2024's calendar repeats in 2052, 2080, 2120, 2148, 2176, and 2216; 2028's in 2056, 2084, 2124, 2152, 2180, and 2220.

Knowing January 1st and whether it's a leap year lets you construct a one-page calendar for any year. Try it—you might find it easier than any other alternative!