Archive

puzzlegame-theoryjane-streetJan 1, 2026

Javelin toss

How should you counter the tosser who doesn't know you know they're cheating?

physicsdifferential-geometryotherDec 27, 2025

Covariant derivative

Where does it come form, how do we find it?

physicsdiffusionotherDec 10, 2025

First passage time

How long until a particle diffuses to $x$?

puzzlegeometryfiddlerDec 8, 2025

Can you fling the fractal darts?

How many points will you asymptotically approach?

puzzlegeometryfiddlerNov 16, 2025

Garden hose

How far is the thirsty random tree from the gushing random hose?

puzzleprobabilityfiddlerNov 8, 2025

Randy hall

How should you move in order to be unpredictable?

puzzlegame-theoryjane-streetNov 1, 2025

Robot baseball

How common can league office scheming rig full counts to be?

puzzleprobabilityfiddlerSep 7, 2025

High low

Where will you be when you can't stop winning?

puzzleprobabilityjane-streetAug 1, 2025

Robot road trip

How much time will you lose avoiding a tragic collision?

puzzleprobabilityfiddlerJul 22, 2025

Can you meet me at the mall?

What is the greatest number of friends you're likely to meet if nobody deigns to coordinate?

puzzlegeometryfiddlerJun 8, 2025

Can you weave the web?

What is the probability that two random points form a line that goes through a particular point $\mathbf{p}$?

puzzleprobabilityfiddlerMay 23, 2025

How long is the river?

What should we expect from coincidental diagonals of contiguous spaces?

puzzlealgorithmsfiddlerMay 18, 2025

Can you permeate the bipyramid?

How many paths can you find?

puzzleprobabilityfiddlerMay 4, 2025

How many rides can you reserve?

How many rides will you get if you throw Mickey a little money on the side?

puzzleprobabilityjane-streetApr 30, 2025

Sum one, somewhere

What's the chance the somebody comes across just zero or one labels on an unending walk down a binary tree with nodes randomly blessed with a label?

puzzlegame-theoryfiddlerApr 21, 2025

Hammer golf

Live by the hammer, die by the hammer.

puzzleprobabilityfiddlerMar 24, 2025

Infinite march madness

How often will the $1$-seed make the final four when there are $(2^d-1)$ worse teams in their region?

puzzlegeometryfiddlerMar 16, 2025

Diametric shore

If you wake up in a random spot on a semi-circular island, how far is the beach, probably?

puzzlegeometryfiddlerFeb 2, 2025

Can you spin the graph?

If you tumble your function is it still a function?

puzzleprobabilityfiddlerJan 25, 2025

Can you hop to the lily pad?

The further you go, the harder it gets.

puzzlegeometryjane-streetDec 1, 2024

Lines of equidistance

What's the chance that two random points in the square are equidistant from some random point on the side that's closest to one of them?

puzzlephysicsfiddlerNov 17, 2024

Stable tiles

How to defy the laws of physics in service of age 3+ entertainment.

puzzleprobabilityfiddlerOct 14, 2024

Peloton leaderboard

How great will you be if you're average in the middle?

puzzlegame-theoryjane-streetSep 1, 2024

Tree-edge triage

Can you taunt your friend forever?

puzzleprobabilityfiddlerAug 26, 2024

Drifting around

How often will the round of the sums be the sum of the rounds?

puzzleprobabilityfiddlerAug 11, 2024

Judging judging

How often are we penalizing our bravest gymnasts?

puzzleprobabilityfiddlerJul 17, 2024

Lose to win

Can you lose the points while winning the match?

puzzleprobabilityfiddlerJun 9, 2024

Can you witness an epic collapse?

How often will Indianapolis get its dreams crushed?

puzzleprobabilityfiddlerJun 1, 2024

Interview line splitting

What is the sum of the products of endless division?

puzzlegeometryfiddlerMay 19, 2024

The radius of a rectangle

What would the world look like if you could only see squares?

puzzlealgorithmsfiddlerMay 6, 2024

Can you beat the heats?

A good old racetrack whodunit.

puzzlegame-theoryjane-streetMay 1, 2024

Capture the flag

How often can you win when you have a number and they have an arrow?

puzzleprobabilityfiddlerApr 21, 2024

Card collisions

What's the chance no card sees its own reflection?

puzzleprobabilityfiddlerApr 9, 2024

Paint by number

Cluster your expectations

puzzlegeometryjane-streetFeb 19, 2024

Pick a circle, any circle

What chance is there, for a circle inside a square?

puzzleprobabilityfiddlerOct 23, 2023

Traffic light chase

How long until you meet your menacing assailant?

puzzleprobabilityfiddlerOct 1, 2023

Pinball lights

How many shots does it take to turn the lights on?

puzzleprobabilityfiddlerSep 18, 2023

Unbalanced league

How often will geography rob your team of a playoff berth?

puzzlegeometryfiddlerSep 10, 2023

Cool weave curve

What shape is the margin doodle?

puzzlegeometryjane-streetAug 8, 2023

Buffon's prism

If you throw a rod into a jelly lattice, what is the chance it crosses just one wall?

puzzlenumber-theoryfiddlerJul 9, 2023

Twisted balkanization

How many different adventures does the Mobius prism have in store?

puzzleprobabilityfivethirtyeightJun 18, 2023

A chancy race

Will the coiners flip before you roll?

puzzleprobabilityfivethirtyeightMay 22, 2023

Take a number

When should you stop dreaming of a brighter future?

puzzleprobabilityfivethirtyeightMay 15, 2023

Save the world

Good use of polling or bad use of polling?

puzzleprobabilityfivethirtyeightApr 9, 2023

Hard choices for the easter bunny

Hoppity hop, which carton are you going to get?

puzzleprobabilityotherApr 6, 2023

Left handed sister

Are you talking to some brother, or the brother?

puzzlegame-theoryjane-streetApr 1, 2023

Robot long jump

Jump late, and long, but not too late.

puzzleprobabilityfivethirtyeightMar 26, 2023

NCAA quota bracket

I'll take one of each.

puzzlephysicsfivethirtyeightMar 12, 2023

Fast times at the marble track

It won't be long before this marble's at your door

puzzleprobabilityfivethirtyeightFeb 19, 2023

Sicilian solitaire

There's nothing to do and there's nothing to win

puzzlegeometryfivethirtyeightFeb 11, 2023

The chance in our stars

A cool puzzle for planes that fly at $\approx 0\,\text{mph}.$

puzzleprobabilityfivethirtyeightFeb 3, 2023

Keep on singing

Will you get to zero bottles of beer on the wall before someone loses their cool?

puzzlegeometryjane-streetJan 28, 2023

Chain of squares

How long can you keep your square away from the covetous origin?

puzzlegeometryfivethirtyeightJan 21, 2023

Drone delivery

How much shorter as the crow flies?

puzzlegame-theoryfivethirtyeightJan 8, 2023

The dark forest

How long will you wait to get off your assemblers?

puzzleprobabilityfivethirtyeightDec 17, 2022

Secret santa administrivia

How long must you wait to pawn your candle off on some poor relative?

puzzleprobabilityfivethirtyeightDec 11, 2022

Soccer brackets

Who will win when anything is possible?

puzzleprobabilityfivethirtyeightDec 7, 2022

Soccer buses

How many trips will the poor saps have to make?

puzzlegeometryfivethirtyeightNov 13, 2022

Reasonable sandwich

How often will the hand of fate deliver a reasonable slice to the undercard?

puzzlephysicsfivethirtyeightNov 13, 2022

Speedy hammer

Will the giant hammer be going fast enough when it hits the big elf door?

puzzleprobabilityfivethirtyeightNov 6, 2022

Fall colors

When's the best time to go leaf peeping?

puzzleprobabilityfivethirtyeightOct 29, 2022

Neurotic halloween

How close can you get to perfect candy disbursement?

puzzleprobabilityfivethirtyeightOct 29, 2022

Loteria lightning

One solitary soul won Mexican bingo, what are the chances?

puzzleprobabilityfivethirtyeightOct 15, 2022

Birthday collisions

How many people in this room have stolen your birthday?

puzzleprobabilityfivethirtyeightOct 9, 2022

Sock wash

Will you be able to fit all your lonely socks on the chair?

puzzleprobabilityfivethirtyeightSep 25, 2022

Letters from the sea

How many letters are you going to have to read?

puzzlealgorithmsfivethirtyeightSep 19, 2022

Too many anigrams

How many generations of humanity will pass before anigrams has a repeat?

puzzleprobabilityfivethirtyeightAug 29, 2022

Traffic groups

How many will go as fast as they want if everyone goes as fast as they want?

puzzleprobabilityjane-streetJul 26, 2022

Morning walkabout

Will the friendly ant have an unusual experience?

puzzlegeometryfivethirtyeightJul 3, 2022

Hide and go seek tower

Now you see me, now you don't

puzzleprobabilityfivethirtyeightJun 25, 2022

Goat tower penthouse

What's the chance this unlucky entrepreneur will have to finance a goat party?

puzzleprobabilityfivethirtyeightJun 19, 2022

Colorful balls

How many do they have?

puzzlephysicsfivethirtyeightJun 11, 2022

Grasshopper jumps

Where will you find this beautiful and mysterious creature?

puzzleprobabilityfivethirtyeightJun 5, 2022

Introverts' exodus

Can you get some privacy on your last walk into the great beyond?

puzzleprobabilityfivethirtyeightMay 22, 2022

Sag A* alignment

Here's lookin' at you kid.

puzzleprobabilityfivethirtyeightMay 14, 2022

Different dice

Get absorbed by these dice.

puzzleprobabilityfivethirtyeightMay 7, 2022

Broken elevator

How many times will you press the broken button?

puzzleprobabilityfivethirtyeightMay 1, 2022

Antipersistent basketball

Who will win if nobody cares until they're losing?

puzzleprobabilityfivethirtyeightApr 23, 2022

A gem of a time

How many gems will you spend on the way to the top?

puzzlephysicsfivethirtyeightFeb 6, 2022

Rotating light

How much light can you spin with a series of filters?

puzzleprobabilityfivethirtyeightJan 29, 2022

Calendrical oil change

How fresh is the oil in your jalopy if you only change a quart per month?

puzzlealgorithmsfivethirtyeightNov 22, 2021

Hat hostage strategies II

Can the ghost of Darwin get you out of this bind?

puzzleprobabilityfivethirtyeightNov 14, 2021

Stick it to the genie

How much can you bilk the genie for?

puzzlegame-theoryjane-streetOct 31, 2021

Robot races

How can you break from the crystalline grip of Nash equilibrists?

puzzleprobabilityfivethirtyeightOct 30, 2021

Squid game

How many will die crossing this entropic bridge?

puzzlegeometryfivethirtyeightOct 24, 2021

Genetic triangles

Will a random baby triangle cover the center of its equilateral parent?

puzzleprobabilityfivethirtyeightOct 17, 2021

Free pete rose

Guess what happens in two world series games to win it all.

puzzlegeometryfivethirtyeightOct 11, 2021

Doppelganger standoff

You're being stalked by a replica who's twice as fast and a genius at hiding behind light poles. Where could they be?

puzzleprobabilityfivethirtyeightSep 10, 2021

Strip paper

How many random cuts before a sheet turns into all strips?

puzzlegame-theoryjane-streetSep 1, 2021

Robot tug of war

Where should the rope start to make robot tug of war fair?

puzzleprobabilityfivethirtyeightAug 30, 2021

$t$ is for tackle

How fast must you sprint to tackle a $15\,\text{mph}$ returner?

puzzleprobabilityfivethirtyeightAug 22, 2021

Uniform dice

How close to uniform can you make the sum of two loaded die?

puzzleprobabilityfivethirtyeightAug 16, 2021

Maximum dice

How high can your score get with optimal freeze-and-reroll?

puzzlegeometryfivethirtyeightJul 31, 2021

Things have chained

What curve does an infinite shrinking chain trace?

puzzlealgorithmsfivethirtyeightJul 25, 2021

Random rock climb

How many random holds until a $10\,\text{m}$ wall is climbable?

puzzlegame-theoryjane-streetJul 21, 2021

Robot weightlifters

How should three robot lifters choose weights to maximize their odds to win?

puzzlegames-logicfivethirtyeightMay 17, 2021

Survivor

Who survives the race-to-20 counting game?

puzzleprobabilityfivethirtyeightMay 2, 2021

Cornhole connoisseur

Who should throw when you need exactly three points to win?

puzzleprobabilityfivethirtyeightApr 24, 2021

Election comeback

What's the chance of a comeback when late ballots lean your way?

puzzlegeometryfivethirtyeightApr 18, 2021

Crescent observatory

How much quicker does the Moon brighten at half than at a slim crescent?

puzzleprobabilityfivethirtyeightMar 27, 2021

A permutation most foul

How many foul-shot orders tie for best in a quirky 3-on-3?

puzzleprobabilityfivethirtyeightMar 7, 2021

Mike trout numerology

Can a batting average’s first digits match games played?

puzzlecombinatoricsfivethirtyeightFeb 28, 2021

Multiverse carpentry

How many universes spawn from every possible staircase order?

puzzleprobabilityfivethirtyeightFeb 21, 2021

Random reverse jenga

How tall can reverse Jenga get before it tumbles?

puzzleprobabilityfivethirtyeightFeb 7, 2021

Random towers

How many moves until random Tower of Hanoi finishes?

puzzleprobabilityfivethirtyeightJan 24, 2021

Gaussian skiers

How safe are you for winning the first heat?

puzzleprobabilityfivethirtyeightJan 10, 2021

Hit the bullseye, kind of

How long can your closer-and-closer dart streak last?

puzzleprobabilityfivethirtyeightDec 19, 2020

Living on the edge

What are the odds the secret-password coaster falls in?

puzzlealgorithmsfivethirtyeightDec 12, 2020

Hat hostage strategies

Can two rows of captives guarantee a hat-color win?

puzzleprobabilityfivethirtyeightNov 22, 2020

Pass the cranberry sauce

Where do you drop the sauce so Uncle Zach gets it last?

puzzleprobabilityfivethirtyeightNov 16, 2020

Total collapse

How often does a 99% coin-flip favorite implode?

puzzleprobabilityfivethirtyeightNov 15, 2020

Final jeopardy

Which board order wins more money if you ace every clue?

puzzleprobabilityfivethirtyeightNov 9, 2020

Fair unfair coins

For how many biases can three flips fake a fair coin?

puzzleprobabilityfivethirtyeightNov 8, 2020

Not a Marathon

Which treadmill run is faster: steady pace or end-of-run sprint?

puzzlecombinatoricsfivethirtyeightNov 1, 2020

It's pumpkin time

When does David S. Pumpkins boot you from the circle?

puzzleprobabilityfivethirtyeightOct 24, 2020

The battle of Los Angeles

Can LeBron steal enough to beat AD in king of the court?

puzzleprobabilityfivethirtyeightOct 21, 2020

Simple runoff elections

How often do random elections force a runoff?

puzzleprobabilityfivethirtyeightOct 18, 2020

The price is wrong

How do you bid when no one knows any prices anymore?

puzzlegeometryfivethirtyeightOct 11, 2020

A tale of two u-turns

How tight a turn saves the stranded grocery run?

puzzlealgorithmsfivethirtyeightSep 20, 2020

Wordly wise

How many guesses to find the secret word in a giant dictionary?

puzzleprobabilityfivethirtyeightSep 13, 2020

Tour de 538

How bad is a bike race when your teammate rage-quits?

puzzleprobabilityfivethirtyeightAug 28, 2020

An end to war

How many lifetimes to see a flawless War victory?

puzzleprobabilityfivethirtyeightAug 17, 2020

Broken ruler

When your ruler shatters, where does the 6-inch shard fall?

puzzleprobabilityfivethirtyeightAug 9, 2020

Nematode addition

How reliable is worm math when your CPU is a petri dish?

puzzlecombinatoricsfivethirtyeightAug 3, 2020

Frustrated graduation

What’s the smallest class where musical chairs always fails?

puzzleprobabilityfivethirtyeightJul 19, 2020

A trip down rubber band road

How long should hare wait on a magically stretching road?

puzzlecombinatoricsfivethirtyeightJul 12, 2020

Trillions of toy towers

How many ways can baby architects stack these tapering rings?

puzzleprobabilityfivethirtyeightJul 4, 2020

Social distance swimming pool

How many swimmers get waved off in the pandemic pool rush?

puzzlegeometryfivethirtyeightJun 26, 2020

Knockoff polygons

How many look-alike polygons can you squeeze from one dot set?

puzzlealgorithmsfivethirtyeightJun 21, 2020

Golden sphere inheritance

How do you split a solid gold sphere fairly?

puzzleprobabilityfivethirtyeightJun 13, 2020

Bacterial collapse

Will these reckless microbes form a dynasty or disappear from the annals of history?

puzzlegeometryfivethirtyeightJun 6, 2020

Sign markers

Where do you dot to keep the ink perfectly even?

puzzleprobabilityfivethirtyeightJun 1, 2020

Wherefore art thou superzoomer

What’s the chance one caller overlaps everyone on Zoom?

puzzlecombinatoricsfivethirtyeightMay 22, 2020

State fish

Can every state land its own perfect fish?

puzzleprobabilityfivethirtyeightApr 11, 2020

Spam attack

How long until spam buries the inbox?

puzzlegame-theoryfivethirtyeightFeb 21, 2020

Flipping coins to freedom

How do you survive 100 flips with two risky coins?

puzzlealgorithmsfivethirtyeightJan 6, 2020

Fast spelling bee

Can you build the ultimate Spelling Bee board?

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