Regularly.co | Puzzles for the inquisitive mind
@regularypuzzles.bsky.social
Hand-crafted puzzles made for the morning commute (https://regularly.co)
Six numbers. One target: 611. Make it from [50, 7, 6, 1, 10, 2]. There’s an elegant route if you spot it.
regularly.co/countable
regularly.co/countable
February 6, 2026 at 6:00 AM
Six numbers. One target: 611. Make it from [50, 7, 6, 1, 10, 2]. There’s an elegant route if you spot it.
regularly.co/countable
regularly.co/countable
Quick question: why do we turn the car radio down when we’re hunting for a house number? Your brain has one pot of attention. Sound steals some, so you turn it off to pour more into looking. Make it quieter and, weirdly, you actually feel like you can see better.
February 3, 2026 at 2:00 PM
Quick question: why do we turn the car radio down when we’re hunting for a house number? Your brain has one pot of attention. Sound steals some, so you turn it off to pour more into looking. Make it quieter and, weirdly, you actually feel like you can see better.
Can you make 299 from 75, 25, 50, 100, 7, 8? Looks awkward, but there’s an elegant route if you spot the pattern. Have a go!
regularly.co/countable
regularly.co/countable
February 2, 2026 at 6:00 AM
Can you make 299 from 75, 25, 50, 100, 7, 8? Looks awkward, but there’s an elegant route if you spot the pattern. Have a go!
regularly.co/countable
regularly.co/countable
Ever notice you walk into a room and forget why you went there? Can you figure out why it happens? Doorways act like scene changes: your brain tidies the last task away. Step into a new context, the old goal drops. Walk back and the original room cues it again.
January 31, 2026 at 2:01 PM
Ever notice you walk into a room and forget why you went there? Can you figure out why it happens? Doorways act like scene changes: your brain tidies the last task away. Step into a new context, the old goal drops. Walk back and the original room cues it again.
Six numbers. One target. Make 489 from 25, 6, 4, 9, 3, 8. There’s an elegant solution if you spot it.
regularly.co/countable
regularly.co/countable
January 30, 2026 at 6:00 AM
Six numbers. One target. Make 489 from 25, 6, 4, 9, 3, 8. There’s an elegant solution if you spot it.
regularly.co/countable
regularly.co/countable
Can you figure out why stepping on a switched-off escalator feels wrong? Your body expects the stairs to move and has already prepared a tiny balance correction. When they don’t, that automatic lean throws you off for a moment.
January 27, 2026 at 2:00 PM
Can you figure out why stepping on a switched-off escalator feels wrong? Your body expects the stairs to move and has already prepared a tiny balance correction. When they don’t, that automatic lean throws you off for a moment.
960 from [25, 75, 100, 50, 10, 2]. Looks hefty, but there’s an elegant route if you spot it. Ready to play?
regularly.co/countable
regularly.co/countable
January 26, 2026 at 6:00 AM
960 from [25, 75, 100, 50, 10, 2]. Looks hefty, but there’s an elegant route if you spot it. Ready to play?
regularly.co/countable
regularly.co/countable
Can you figure out why your voice sounds odd on recordings? Day to day you hear two versions at once: through the air and a deeper buzz carried through your head. A recording only has the air one, so the warm low notes vanish and you sound thinner.
January 24, 2026 at 2:00 PM
Can you figure out why your voice sounds odd on recordings? Day to day you hear two versions at once: through the air and a deeper buzz carried through your head. A recording only has the air one, so the warm low notes vanish and you sound thinner.
Quick challenge: make 536 from 50, 10, 7, 6, 1, 9. Looks tricky, but there’s an elegant solution if you spot the pairing. Fancy a go?
regularly.co/countable
regularly.co/countable
January 23, 2026 at 6:00 AM
Quick challenge: make 536 from 50, 10, 7, 6, 1, 9. Looks tricky, but there’s an elegant solution if you spot the pairing. Fancy a go?
regularly.co/countable
regularly.co/countable
Can you figure out why alarm snooze is usually nine minutes? Early alarm clocks could only manage roughly nine, and the habit stuck. It also feels like a cheeky top-up: long enough to be nice, short enough that you don’t tumble back into deep sleep.
January 20, 2026 at 2:00 PM
Can you figure out why alarm snooze is usually nine minutes? Early alarm clocks could only manage roughly nine, and the habit stuck. It also feels like a cheeky top-up: long enough to be nice, short enough that you don’t tumble back into deep sleep.
808. Six numbers. One target. [3, 5, 8, 2, 4, 9] Can you spot the pattern? There’s a surprisingly elegant route if you do.
regularly.co/countable
regularly.co/countable
January 19, 2026 at 6:00 AM
808. Six numbers. One target. [3, 5, 8, 2, 4, 9] Can you spot the pattern? There’s a surprisingly elegant route if you do.
regularly.co/countable
regularly.co/countable
Can you figure out why supermarkets put the milk and bread right at the back? So you walk past snacks and offers on the way. Those everyday essentials pull you in, and by placing them deep inside, the shop quietly tempts you to pick up a few extras en route.
January 17, 2026 at 2:00 PM
Can you figure out why supermarkets put the milk and bread right at the back? So you walk past snacks and offers on the way. Those everyday essentials pull you in, and by placing them deep inside, the shop quietly tempts you to pick up a few extras en route.
Quick one: make 879 using [25, 2, 10, 4, 1, 7]. Looks tame, but there's an elegant route if you spot it. Fancy a go?
regularly.co/countable
regularly.co/countable
January 16, 2026 at 6:00 AM
Quick one: make 879 using [25, 2, 10, 4, 1, 7]. Looks tame, but there's an elegant route if you spot it. Fancy a go?
regularly.co/countable
regularly.co/countable
Think a fair coin makes this 50-50? Start at 0, move +1 for heads and -1 for tails, stop at +1 or -2. The chance you hit +1 first is 2/3. Why? If p is that chance, the expected final position is 0: p*1 + (1-p)*(-2) = 0, so p = 2/3. Still feel 50-50?
January 14, 2026 at 2:01 PM
Think a fair coin makes this 50-50? Start at 0, move +1 for heads and -1 for tails, stop at +1 or -2. The chance you hit +1 first is 2/3. Why? If p is that chance, the expected final position is 0: p*1 + (1-p)*(-2) = 0, so p = 2/3. Still feel 50-50?
Monday's Countable number is: 687
Can you get to it only using 100, 50, 25, 8, 4, and 7?
regularly.co/countable
Can you get to it only using 100, 50, 25, 8, 4, and 7?
regularly.co/countable
January 12, 2026 at 6:00 AM
Monday's Countable number is: 687
Can you get to it only using 100, 50, 25, 8, 4, and 7?
regularly.co/countable
Can you get to it only using 100, 50, 25, 8, 4, and 7?
regularly.co/countable
Curious twist: Does an infinite hotel always have rooms for improvement? Even when “full”, shift guest n to n+1 to free room 1; for infinitely many newcomers, move n to 2n to free all odd rooms. Infinity lets you make vacancies by reindexing, doesn’t it?
January 9, 2026 at 2:00 PM
Curious twist: Does an infinite hotel always have rooms for improvement? Even when “full”, shift guest n to n+1 to free room 1; for infinitely many newcomers, move n to 2n to free all odd rooms. Infinity lets you make vacancies by reindexing, doesn’t it?
Friday's Countable number is: 632
Can you get to it only using 50, 6, 7, 10, 1, and 5?
regularly.co/countable
Can you get to it only using 50, 6, 7, 10, 1, and 5?
regularly.co/countable
January 9, 2026 at 6:00 AM
Friday's Countable number is: 632
Can you get to it only using 50, 6, 7, 10, 1, and 5?
regularly.co/countable
Can you get to it only using 50, 6, 7, 10, 1, and 5?
regularly.co/countable
Fun fact that'll mess with your head: Everyone thinks average speed is the mean of speeds, but actually you average time. Equal distances at 60 and 40 give 48, not 50, because the slow stretch lasts longer. Overall speed = total distance / total time.
January 7, 2026 at 2:01 PM
Fun fact that'll mess with your head: Everyone thinks average speed is the mean of speeds, but actually you average time. Equal distances at 60 and 40 give 48, not 50, because the slow stretch lasts longer. Overall speed = total distance / total time.
Okay this is genuinely wild: in any group of 6, there must be 3 mutual friends or 3 mutual strangers. Pick one person. Among their 5 links, at least 3 are the same type. If any two of those 3 share that type you have a trio; if none do, the 3 are all the other type.
January 5, 2026 at 2:01 PM
Okay this is genuinely wild: in any group of 6, there must be 3 mutual friends or 3 mutual strangers. Pick one person. Among their 5 links, at least 3 are the same type. If any two of those 3 share that type you have a trio; if none do, the 3 are all the other type.
Monday's Countable number is: 899
Can you get to it only using 100, 75, 4, 6, 8, and 5?
regularly.co/countable
Can you get to it only using 100, 75, 4, 6, 8, and 5?
regularly.co/countable
January 5, 2026 at 6:00 AM
Monday's Countable number is: 899
Can you get to it only using 100, 75, 4, 6, 8, and 5?
regularly.co/countable
Can you get to it only using 100, 75, 4, 6, 8, and 5?
regularly.co/countable
Reposted by Regularly.co | Puzzles for the inquisitive mind
Ok I was very lucky today. Paths was my quickest solve and my first wordle was incredibly lucky.
#Paths No.381 (regularly.co/paths)
💡×11 bulbs
Wordle 1,609 2/6
⬜⬜🟩🟩🟨
🟩🟩🟩🟩🟩
#Paths No.381 (regularly.co/paths)
💡×11 bulbs
Wordle 1,609 2/6
⬜⬜🟩🟩🟨
🟩🟩🟩🟩🟩
November 14, 2025 at 2:46 PM
Ok I was very lucky today. Paths was my quickest solve and my first wordle was incredibly lucky.
#Paths No.381 (regularly.co/paths)
💡×11 bulbs
Wordle 1,609 2/6
⬜⬜🟩🟩🟨
🟩🟩🟩🟩🟩
#Paths No.381 (regularly.co/paths)
💡×11 bulbs
Wordle 1,609 2/6
⬜⬜🟩🟩🟨
🟩🟩🟩🟩🟩
Reposted by Regularly.co | Puzzles for the inquisitive mind
November 17, 2025 at 8:52 PM
Here's something weird... Everyone thinks first digits split evenly, but actually 1 is number one. Benford's law: when data span orders of magnitude, logs are uniform, so P(first digit d) = log10(1+1/d). Does that add up, or do you smell a digit trick?
January 3, 2026 at 11:03 AM
Here's something weird... Everyone thinks first digits split evenly, but actually 1 is number one. Benford's law: when data span orders of magnitude, logs are uniform, so P(first digit d) = log10(1+1/d). Does that add up, or do you smell a digit trick?
Saturday's Countable number is: 733
Can you get to it only using 50, 75, 100, 2, 7, and 8?
regularly.co/countable
Can you get to it only using 50, 75, 100, 2, 7, and 8?
regularly.co/countable
January 3, 2026 at 11:02 AM
Saturday's Countable number is: 733
Can you get to it only using 50, 75, 100, 2, 7, and 8?
regularly.co/countable
Can you get to it only using 50, 75, 100, 2, 7, and 8?
regularly.co/countable
Actually... everyone thinks your average bus wait is half the average gap. Not so. Arrive at a random time and you land in long gaps more often. Your wait is half that gap, so long gaps weigh extra. In fact E[wait] = E[gap^2]/(2E[gap]) ≥ mean gap/2, with > unless gaps are equal.
January 2, 2026 at 2:01 PM
Actually... everyone thinks your average bus wait is half the average gap. Not so. Arrive at a random time and you land in long gaps more often. Your wait is half that gap, so long gaps weigh extra. In fact E[wait] = E[gap^2]/(2E[gap]) ≥ mean gap/2, with > unless gaps are equal.