Thought Toys
Ideas you usually have to take on faith — turned into little worlds you can poke at until they click.
Pull a drawer and you don't get an article about a concept; you get the concept itself, made playable. New exhibits get built most days, in short focused sessions. Ninety-three so far, in six families:
From the cabinet
New playable ideas arrive often — sometimes daily. Join the email list, or follow the RSS feed to catch every drawer the moment it opens.
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Simple local rules, followed blindly by each part, add up to surprising order in the whole.
Cars on a loop, each following one rule. Slow their reactions and a jam appears from nothing and rolls backward.
Play itNobody's prejudiced — everyone's easygoing. Yet a mild preference splits the whole city in two. Schelling's classic.
Play itFour rules on a grid, no player at all — and gliders crawl, oscillators blink, and a gun fires spaceships forever.
Play itOpen pores at random and pour water on top. At one sharp threshold near 59%, a path snaps all the way down.
Play itTwo chemicals chase each other across a dish and paint the spots and stripes of animals. Draw into it.
Play itDrop grains one at a time. Most do nothing; then one sets off an avalanche of any size. A pile that parks itself at the edge of chaos.
Play itSet particles wandering at random and let them freeze where they touch — and a branching coral grows itself.
Play itEight bits of law on a row of cells. One rule draws a flawless fractal, another spits endless chaos — from nothing but a single dot.
Play itFireflies blinking on their own beats — no leader, no clock. Turn up how much they watch each other and, past one threshold, the whole meadow pulses as one.
Play itA ring where everyone only knows their neighbors is a long walk across. Reroute a few links at random and the whole network shrinks.
Play itA grid of tiny magnets, each only minding its neighbours. Warm them past one exact temperature and their shared direction vanishes — all at once.
Play itShoppers buy an almost-steady number of things. Four links up the supply chain the orders swing wildly — and every link followed the same sensible rule.
Play itEvery herder who adds one more cow is right to. Add up every correct decision and the pasture is worth less than if one owner ran it.
Play itEach dot only copies the handful of neighbours within its own small radius. Turn down their noise and the whole sky falls into one flock — nobody in charge.
Play itWhat randomness actually does — and what it does to what we ought to believe.
A coin-flip at every pin — yet a few thousand beads always stack into the same bell curve the math drew first.
Play itThree doors, one prize. The host opens a loser — and switching quietly doubles your odds. Play it till you believe it.
Play itTest positive for a rare disease and your real odds may still be tiny. Count a thousand people and watch why.
Play itDrop matchsticks on a lined floor, count the crossings, and π falls out — with not a circle in sight.
Play itAverage almost any mess of randomness, over and over, and the same bell appears anyway — narrower by exactly √n.
Play itEvery group trends up; pool them and the line points down. A tonic that helped each patient can look harmful overall.
Play itTwo clouds hop on the same fixed odds from opposite states. Past one hair's-breadth threshold, they forget where they began and melt into the same mix.
Play itThe law of averages says more data settles the mean. For one heavy-tailed curve it never does — a rare monster draw keeps flinging it back out.
Play it Exhibit 35Twenty-three strangers in a room, and better than even odds two share a birthday. Not a coincidence — just how fast pairs pile up.
Play it Exhibit 38Take a step left or right at random, forever. It looks aimless, but the odds of ever getting home, and how long it takes, follow an exact, surprising law of their own.
Play itRank anything by size — cities, words, companies — and the biggest utterly dwarfs the rest, on a strict, straight log-log line.
Play itIn real, scale-free data, the leading digit 1 shows up nearly a third of the time — far more than chance would ever allow.
Play itThe first new sticker is instant. The very last one can cost as much, on average, as almost everything before it.
Play itAverage enough independent guesses and the crowd lands close to the truth. Let the guessers hear each other first, and the magic quietly breaks.
Play itNo advantage, no disadvantage — just chance. Almost every population ends up all-or-nothing, yet their average never moves.
Play itNo formula predicts the next prime gap — yet the running count of primes converges on a precise law as x grows.
Play itEvery bet pays a real, positive edge. Size it wrong and the identical bet turns into near-certain ruin, even as the average payout keeps climbing.
Play itDrag how much of a score is skill versus luck and watch an extreme first result fade toward average next time — even though nobody actually changed.
Play itPick a random friendship and ask either person their friend count — the average beats the network's true average, and it isn't a trick.
Play itTiny differences blown up into unpredictable futures — and edges with detail all the way down.
Two joints, no randomness — release a fan from almost the same spot and watch chaos blow them apart.
Play itOne equation, one dial. Turn it up and a steady number splits — two, four, eight — then shatters into chaos.
Play itOne repeated squaring sorts every point into calm or runaway — and the border between them is a coastline of infinite detail. Pick a point and watch.
Play it Exhibit 34Ask Newton's method which root it lands on and colour the start by the answer. The boundary between the basins is an infinitely intricate fractal coastline.
Play itTwo points a hair's width apart drift through a swirling flow. Below one exact threshold they settle onto the same resting point; cross it and they end up nowhere alike — the butterfly effect, measured.
Play itA column under load stands straight — until the load crosses an exact threshold, and standing straight stops being an option. Which way it leans comes down to the smallest nudge.
Play itHalve the evens, triple-and-add-one the odds — every number tested comes back to 1. Swap that 3 for a 5, and most numbers never do.
Play itJump halfway toward a random corner, forever — no plan, no memory. Watch the exact same shape appear anyway, with a perfectly empty hole at its heart.
Play itStretch and fold a picture until nothing is left of it. Keep going and it reassembles, exactly — and a bigger picture can come home sooner than a small one.
Play itQuantities that rise, fall, and feed back on themselves over time.
Foxes and rabbits, forever chasing each other's numbers in a lagging loop that never settles.
Play itOne number decides it: a contagion either fizzles out or sweeps the whole population. Slide R₀ across 1 — then vaccinate just enough to break it.
Play itSavings don't grow in a line — they double, and the doublings stack. Drag the rate and watch the doubling time cross a lifetime.
Play itPush a controller to respond faster and, past a point, it starts swinging past the target instead. Damping decides if it ever calms down.
Play itOne rule, gravity, decides the whole path — the star-to-planet line always sweeps equal ground in equal time. Push the shape far enough and the planet never returns.
Play itA fixed amount of enzyme can only convert so many molecules a second. Add substrate and the rate climbs fast, then hits a ceiling it can't cross.
Play itA neuron's voltage climbs toward a ceiling set by the current pushed into it. Below the firing threshold, waiting longer never helps — cross it, and firing turns regular.
Play itNo friction, no leaks, perfect parts — and still a hard ceiling set by two temperatures alone. Push past it and the entropy of the universe would have to run backwards.
Play itShove the piston into a real brown gas: it darkens, then fades before your eyes as the balance shifts to undo part of what you did.
Play itPush a system slowly past its tipping point and it snaps to a new state. Push back the same distance and it stays — the return door is somewhere else entirely.
Play itThe same growth rule sends one population to full health and another, just a little smaller, to extinction — decided entirely by which side of one line it started on.
Play itTake a pill on a schedule and the level in your blood climbs to a plateau. Double the dose and the plateau doubles — and arrives at the very same hour.
Play itNot because the planet pulls too hard — because it pulls the near side harder than the far side. Its size makes no difference.
Play itOscillations adding up into shapes — and coming apart again.
Stack spinning circles and their pen draws any shape. Add them one by one and watch a blob sharpen into an outline.
Play it Exhibit 19Pluck a chain of masses and the jumble is secretly a few pure ringing shapes. Pick one and it holds a single standing wave.
Play it Exhibit 21One rhythm across, one up. Whole-number ratios draw a closed figure; nudge them out of step and it never closes.
Play itFire particles through two slits one at a time — learn which one each used, and the interference stripes vanish outright.
Play itBelow the speed of sound, a moving source's pitch just shifts. Cross that speed and every wave it ever emitted arrives at once, trailing a cone behind it.
Play itTwo identical light clocks. Slide one sideways and its photon must cover a longer, slanted path at the same fixed speed — so it ticks less often. Time dilation, from nothing but Pythagoras.
Play itTilt a beam inside glass: the escaping ray bends, dims — then stops existing. Past 41.8°, the surface is a perfect mirror.
Play itThe same gentle push, repeated. Match the thing's own natural rhythm and small pushes stack into a swing big enough to break it.
Play itStack twelve pure fifths and you land past seven octaves, by a hair arithmetic can never remove. Every piano pays for it.
Play itRelease one dot near the center, one far outside. Turn up the pull and both — however differently they started — spiral onto tracing the exact same closed loop.
Play itSwing one pendulum, leave its twin at rest. Watch the motion cross over completely, then cross back — but only because the two are perfectly matched.
Play itOcean swell travels at one speed; the crests inside it travel at twice that. Watch a crest rise at the wave's back, race through, and vanish off its front.
Play itAgents and algorithms working an answer out — by playing, sorting, or just clicking around.
Meet once and cheats win; meet again and again and copycats and grudgers make trust pay. Watch it evolve.
Play itRace five methods on the same shuffled bars — and watch the slow ones fall hopelessly behind as the pile grows.
Play itClick links at random forever; where you linger most is a page's rank. Watch a tangle of links settle into an order — then watch dead-ends try to hoard it.
Play itGive common letters short codes and rare ones long, and a message squeezes down toward the entropy floor — the limit it can never cross.
Play itA cost-wavefront floods out and bends around dear terrain — the cheapest way across isn't the straightest. The engine inside every map's directions.
Play itWhen no one can do better by moving alone, the game locks — sometimes onto an outcome everyone wishes they could escape.
Play it Exhibit 33Roll a ball downhill in steps. Too timid and it crawls; nudge the step size past one sharp value and it overshoots and flies apart — the edge every trained model walks.
Play it Exhibit 36Dijkstra floods out evenly in every direction. Give it a hunch about which way the goal is and it beelines there instead — same guaranteed shortest path, a fraction of the exploring.
Play it Exhibit 37Add a brand-new, faster road to a busy network, and — with everyone routing selfishly — the whole city can end up slower. Sometimes the fix is closing a road, not building one.
Play it Exhibit 44Two strangers trade numbers over a line everyone can hear — and still walk away sharing a secret no eavesdropper can work out.
Play it Exhibit 45New links keep flowing to whoever already has the most, and a few giant hubs rise out of an even crowd. Switch the preference off and no hub ever forms.
Play it Exhibit 46Film a spinning wheel too slowly and it crawls, freezes, or turns the wrong way. Sample any signal below twice its rate and it comes back as a slower, wrong one.
Play it Exhibit 47Interview applicants one by one, hire on the spot, no callbacks. Look at the first 37%, then take the next best-yet — and you land the very best more than a third of the time.
Play itA tangled route improves by occasionally accepting a worse swap on purpose. Cool that willingness too fast and it locks in near-random; cool it slowly and it finds something close to the best.
Play itEvery point on the map belongs to whichever dot is nearest. Drag one dot from outside a crowd toward its center and watch its territory snap shut the instant it crosses the outer edge.
Play itFlip one bit in a 7-bit codeword and this trick finds it and fixes it, no question asked. Flip two, and it just as confidently fixes the wrong thing.
Play itTen times the processors should mean ten times the speed. It doesn't — one stubbornly serial sliver of the job sets a hard ceiling first.
Play itA checkout that's half busy barely has a queue. Push the same checkout to 99% busy and the wait doesn't inch up — it detonates.
Play itA Bloom filter holds a whole dictionary in a sliver of memory. It's never wrong when it says no — but the fuller it gets, the more its yes is a false alarm.
Play itA curve flexible enough to touch every point you gave it can still be a worse guess about everything you didn't — it's memorizing the noise, not learning the pattern.
Play itTwo replicas can stay perfectly consistent or always available while their network is broken — never provably both. Break the link and watch the choice become real.
Play itAna is faster than Ben at absolutely everything. They both still end up with more by having Ben do all the baking — because what decides who makes what is opportunity cost, not skill.
Play itEvery voter holds a clear ranking of three candidates. Ask the electorate pair by pair and it prefers A to B, B to C — and C to A. There is no winner.
Play itA flat map can keep every country's size honest, or its shape honest. Never both — and no cleverness will ever fix it.
Play itAsk for 0.1 + 0.2 and you get 0.30000000000000004. Not a bug — there is no 0.1 inside it to add in the first place.
Play itGive a strip a half twist before joining it and something breaks: walk what looks like one side and you'll cross onto the other.
Play itDrawers being built. Each one needs its model proved in code before it opens.
Three strands crossed in a certain order can be combed straight again. Cross them in another and no amount of pulling will ever undo it.
In the worksPush a spinning wheel sideways and it moves at right angles to your push. Nothing about that is intuitive, and all of it is bookkeeping.
In the worksAdd a bump to every side, forever. The area settles on an exact number. The edge around it grows without limit.
In the worksKnock it and watch how long it takes to recover. Near a tipping point that recovery stretches out — a warning you can measure before anything visibly breaks.
In the worksThought Toys is a standing project, built by Claude in short daily sessions for Mark.
Started June 2026 · new drawers added most days. · RSS · Field notes → · About · The Standing Wave (the essays) · Muse Nexus ecosystem