Regularly.co | Puzzles for the inquisitive mind
@regularypuzzles.bsky.social
Hand-crafted puzzles made for the morning commute (https://regularly.co)
Pinned
Monday's Countable number is: 497
Can you get to it only using 9, 5, 6, 2, 7, and 3?
regularly.co/countable
Can you get to it only using 9, 5, 6, 2, 7, and 3?
regularly.co/countable
Actually... it's 28 Nov 2025 at 23:08 and I'm in a 24-hour launderette in Hackney watching the dryers orbit. Almost every real number is normal, where every finite digit block shows up with the right frequencies. We still don't know if pi is one of them.
November 28, 2025 at 6:34 AM
Actually... it's 28 Nov 2025 at 23:08 and I'm in a 24-hour launderette in Hackney watching the dryers orbit. Almost every real number is normal, where every finite digit block shows up with the right frequencies. We still don't know if pi is one of them.
Friday's Countable number is: 798
Can you get to it only using 75, 3, 7, 4, 10, and 9?
regularly.co/countable
Can you get to it only using 75, 3, 7, 4, 10, and 9?
regularly.co/countable
November 28, 2025 at 6:33 AM
Friday's Countable number is: 798
Can you get to it only using 75, 3, 7, 4, 10, and 9?
regularly.co/countable
Can you get to it only using 75, 3, 7, 4, 10, and 9?
regularly.co/countable
Okay this is genuinely wild: Unpopular opinion: you can take a solid ball, cut it into finitely many pieces, and reassemble two balls the same size. No stretching. Everyone swears you can't. Guess what assumption you have to quietly accept for this to be "legal"?
November 26, 2025 at 1:08 AM
Okay this is genuinely wild: Unpopular opinion: you can take a solid ball, cut it into finitely many pieces, and reassemble two balls the same size. No stretching. Everyone swears you can't. Guess what assumption you have to quietly accept for this to be "legal"?
Wednesday's Countable number is: 873
Can you get to it only using 50, 100, 25, 2, 5, and 3?
regularly.co/countable
Can you get to it only using 50, 100, 25, 2, 5, and 3?
regularly.co/countable
November 26, 2025 at 1:06 AM
Wednesday's Countable number is: 873
Can you get to it only using 50, 100, 25, 2, 5, and 3?
regularly.co/countable
Can you get to it only using 50, 100, 25, 2, 5, and 3?
regularly.co/countable
Everyone thinks "full" means no vacancies, but actually Hilbert's Hotel still has room for improvement: send guest n to n+1 and check in infinitely many more.
November 25, 2025 at 2:38 PM
Everyone thinks "full" means no vacancies, but actually Hilbert's Hotel still has room for improvement: send guest n to n+1 and check in infinitely many more.
Tuesday's Countable number is: 767
Can you get to it only using 25, 75, 100, 7, 5, and 3?
regularly.co/countable
Can you get to it only using 25, 75, 100, 7, 5, and 3?
regularly.co/countable
November 25, 2025 at 2:38 PM
Tuesday's Countable number is: 767
Can you get to it only using 25, 75, 100, 7, 5, and 3?
regularly.co/countable
Can you get to it only using 25, 75, 100, 7, 5, and 3?
regularly.co/countable
Here's something weird: there’s a shape with finite volume but infinite surface area. You can fill it with paint, but you can never paint the outside. Calculus says so. Gabriel’s Horn.
November 24, 2025 at 2:00 PM
Here's something weird: there’s a shape with finite volume but infinite surface area. You can fill it with paint, but you can never paint the outside. Calculus says so. Gabriel’s Horn.
Monday's Countable number is: 329
Can you get to it only using 25, 75, 50, 100, 5, and 9?
regularly.co/countable
Can you get to it only using 25, 75, 50, 100, 5, and 9?
regularly.co/countable
November 24, 2025 at 6:00 AM
Monday's Countable number is: 329
Can you get to it only using 25, 75, 50, 100, 5, and 9?
regularly.co/countable
Can you get to it only using 25, 75, 50, 100, 5, and 9?
regularly.co/countable
Sunday's Countable number is: 262
Can you get to it only using 50, 100, 75, 25, 3, and 8?
regularly.co/countable
Can you get to it only using 50, 100, 75, 25, 3, and 8?
regularly.co/countable
November 23, 2025 at 9:39 PM
Sunday's Countable number is: 262
Can you get to it only using 50, 100, 75, 25, 3, and 8?
regularly.co/countable
Can you get to it only using 50, 100, 75, 25, 3, and 8?
regularly.co/countable
Tried to join a group; it wasn’t closed, had no identity, and the inverses never showed. Felt more like a set.
November 23, 2025 at 2:00 PM
Tried to join a group; it wasn’t closed, had no identity, and the inverses never showed. Felt more like a set.
Plot twist: I fell for a complex number. It was imaginary, and our arguments just went in circles.
November 22, 2025 at 9:19 PM
Plot twist: I fell for a complex number. It was imaginary, and our arguments just went in circles.
Saturday's Countable number is: 136
Can you get to it only using 50, 100, 75, 25, 2, and 4?
regularly.co/countable
Can you get to it only using 50, 100, 75, 25, 2, and 4?
regularly.co/countable
November 22, 2025 at 9:08 PM
Saturday's Countable number is: 136
Can you get to it only using 50, 100, 75, 25, 2, and 4?
regularly.co/countable
Can you get to it only using 50, 100, 75, 25, 2, and 4?
regularly.co/countable
Pick a random chord in a circle: what’s the probability it’s longer than a side of the inscribed equilateral triangle, and which notion of random were you imagining?
November 21, 2025 at 2:00 PM
Pick a random chord in a circle: what’s the probability it’s longer than a side of the inscribed equilateral triangle, and which notion of random were you imagining?
Friday's Countable number is: 558
Can you get to it only using 25, 50, 75, 3, 9, and 8?
regularly.co/countable
Can you get to it only using 25, 50, 75, 3, 9, and 8?
regularly.co/countable
November 21, 2025 at 6:00 AM
Friday's Countable number is: 558
Can you get to it only using 25, 50, 75, 3, 9, and 8?
regularly.co/countable
Can you get to it only using 25, 50, 75, 3, 9, and 8?
regularly.co/countable
Probability that feels like a prank: a random walk on an infinite 2D grid returns to its start with probability 1. In 3D the same wanderer probably never returns. One extra direction is enough to get lost.
November 20, 2025 at 7:52 AM
Probability that feels like a prank: a random walk on an infinite 2D grid returns to its start with probability 1. In 3D the same wanderer probably never returns. One extra direction is enough to get lost.
Thursday's Countable number is: 331
Can you get to it only using 75, 4, 7, 10, 1, and 5?
regularly.co/countable
Can you get to it only using 75, 4, 7, 10, 1, and 5?
regularly.co/countable
November 20, 2025 at 7:51 AM
Thursday's Countable number is: 331
Can you get to it only using 75, 4, 7, 10, 1, and 5?
regularly.co/countable
Can you get to it only using 75, 4, 7, 10, 1, and 5?
regularly.co/countable
19 Nov 2025, 22:21, window seat in Soho, buses hissing on wet tarmac. Two games both losing in the long run. Mix their order right and you come out ahead. Parrondo’s paradox. My brain keeps checking for a catch.
November 19, 2025 at 2:00 PM
19 Nov 2025, 22:21, window seat in Soho, buses hissing on wet tarmac. Two games both losing in the long run. Mix their order right and you come out ahead. Parrondo’s paradox. My brain keeps checking for a catch.
Most people believe games should be transitive, but here's the twist: there are dice A, B and C where A tends to beat B, B beats C, and C beats A. If I let you choose first, which die are you taking and why?
November 17, 2025 at 2:10 PM
Most people believe games should be transitive, but here's the twist: there are dice A, B and C where A tends to beat B, B beats C, and C beats A. If I let you choose first, which die are you taking and why?
Monday's Countable number is: 497
Can you get to it only using 9, 5, 6, 2, 7, and 3?
regularly.co/countable
Can you get to it only using 9, 5, 6, 2, 7, and 3?
regularly.co/countable
November 17, 2025 at 6:00 AM
Monday's Countable number is: 497
Can you get to it only using 9, 5, 6, 2, 7, and 3?
regularly.co/countable
Can you get to it only using 9, 5, 6, 2, 7, and 3?
regularly.co/countable
Most people think 0^0 is undefined, but here's the thing: in combinatorics it needs to be 1. I write x=0 on a napkin and slide it across the table. If it isn't 1, the binomial theorem snaps. What happens next?
November 14, 2025 at 2:00 PM
Most people think 0^0 is undefined, but here's the thing: in combinatorics it needs to be 1. I write x=0 on a napkin and slide it across the table. If it isn't 1, the binomial theorem snaps. What happens next?
Friday's Countable number is: 657
Can you get to it only using 75, 50, 10, 8, 6, and 4?
regularly.co/countable
Can you get to it only using 75, 50, 10, 8, 6, and 4?
regularly.co/countable
November 14, 2025 at 6:00 AM
Friday's Countable number is: 657
Can you get to it only using 75, 50, 10, 8, 6, and 4?
regularly.co/countable
Can you get to it only using 75, 50, 10, 8, 6, and 4?
regularly.co/countable
Hints are now live on Countable - thanks @29rory.bsky.social for the excellent suggestion! 🧩
Thanks for the excellent suggestion! We've implemented hints into countable so you can discover the shortest solution line by line.
Do tell us if it works well for you, and please do keep the suggestions coming if you have anymore. We really appreciate them :)
Do tell us if it works well for you, and please do keep the suggestions coming if you have anymore. We really appreciate them :)
November 12, 2025 at 11:34 AM
Hints are now live on Countable - thanks @29rory.bsky.social for the excellent suggestion! 🧩
11 Nov 2025, 19:12, Northern line between Euston and Kentish Town: we flip a fair coin until the first heads. You must choose odd or even number of flips before we start. Which choice secretly wins more often? I’m about to wager on it; who ends up buying the tea?
November 11, 2025 at 8:07 PM
11 Nov 2025, 19:12, Northern line between Euston and Kentish Town: we flip a fair coin until the first heads. You must choose odd or even number of flips before we start. Which choice secretly wins more often? I’m about to wager on it; who ends up buying the tea?
Tuesday's Countable number is: 457
Can you get to it only using 75, 25, 100, 50, 3, and 10?
regularly.co/countable
Can you get to it only using 75, 25, 100, 50, 3, and 10?
regularly.co/countable
November 11, 2025 at 8:06 PM
Tuesday's Countable number is: 457
Can you get to it only using 75, 25, 100, 50, 3, and 10?
regularly.co/countable
Can you get to it only using 75, 25, 100, 50, 3, and 10?
regularly.co/countable
Reposted by Regularly.co | Puzzles for the inquisitive mind
Decent Kingly and Wordle today 🎉
#Kingly No.140 (regularly.co/kingly)
✅ Solved in 88 moves
Wordle 1,606 4/6
⬜⬜⬜🟨⬜
⬜🟨⬜⬜⬜
🟨🟨🟨⬜⬜
🟩🟩🟩🟩🟩
#Kingly No.140 (regularly.co/kingly)
✅ Solved in 88 moves
Wordle 1,606 4/6
⬜⬜⬜🟨⬜
⬜🟨⬜⬜⬜
🟨🟨🟨⬜⬜
🟩🟩🟩🟩🟩
November 11, 2025 at 7:13 AM
Decent Kingly and Wordle today 🎉
#Kingly No.140 (regularly.co/kingly)
✅ Solved in 88 moves
Wordle 1,606 4/6
⬜⬜⬜🟨⬜
⬜🟨⬜⬜⬜
🟨🟨🟨⬜⬜
🟩🟩🟩🟩🟩
#Kingly No.140 (regularly.co/kingly)
✅ Solved in 88 moves
Wordle 1,606 4/6
⬜⬜⬜🟨⬜
⬜🟨⬜⬜⬜
🟨🟨🟨⬜⬜
🟩🟩🟩🟩🟩