Every App on pinkelephant.space — a Field Guide

July 8, 2026 · 20 min read · updated August 28, 2026

Half the reason this site exists is to make small things that help someone else — games for kids, calculators, tiny toys that teach one idea. Here’s the full catalog so far, grouped by kind.

The home page has every name, link, and keyword, plus search and a like button. This article explains why each thing exists, and the parts you’d miss at a glance.

A few notes that apply to almost all of them: no account, no ads, no tracking. Most work offline once loaded. Many are built for a phone you hand to a kid, or a room full of friends.

Games — action & arcade

Pure play. Pick one up, learn it in a minute.

App	Keywords	What it is, and the non-obvious part
1v1	shooting, duel, pvp	A top-down shooting duel with AI. Aim matters — without it you miss, even at close range.
3D Shooting	fps, aim, action	A first-person aim-and-shoot in 3D.
Apple Catch	catch, arcade, kids	Catch falling apples in a bucket. The twist: the bucket shrinks as you go.
Ball	runner, endless, reflex	An endless roller: jump over the gaps.
Black Hole Eater	growth, risk, arcade	Steer a black hole and swallow everything smaller than you. Grow too greedy and a red ring ends the run — the whole game is knowing when the next bite isn’t worth it.
Cactus	jump, runner, dinosaur	The Chrome “no internet” dinosaur game, rebuilt. Jump the cactuses — and watch for the birds.
Chef	cooking, time management	A kitchen time-management game: take orders, serve before the timer ends.
Connect 4	connect four, strategy, family	Duel with AI. A good five minutes with a kid, and a first lesson in strategy: set up two threats at once so they can’t block both.
Gravity flip	gravity, platformer, reflex	Flip gravity to dodge obstacles — a platformer where “up” is a choice. Incredibly difficult for humans. Challenging for AI too.
Loop	racing, driving, track	Drive a lap around a track as fast as you can. The easiest task to train AI on.
Monster Attack	survival, waves, action	Survive waves of monsters. Collect all the powers.
Plaza	racing, drift, arcade	Arcade racing with drift.
Racer	racing, speed, track	Sharp turns create non-smooth gradients. That makes it hard for AI to adapt with a speciated genetic algorithm.
Snake	classic, retro, high score	The Nokia classic. Coil neatly along the walls so you never trap your own tail. Mathematically solved for all even board sizes.
Space Shooting	space, aliens, retro	A retro top-down space shooter — your ship, endless waves of aliens.
Swarm	bees, survival, waves	Survive a swarm of enemies. The AI is a sharp shooter. You keep moving and leading them away.
Tetris	blocks, classic, ai	Turn-based Tetris — take your time to plan and act, with an AI that will play for you.
Topview Shooting	shooter, aim, survival	A top-down shooter: aim, move, survive the waves.
Tower Defence	strategy, towers, upgrade	Place towers, upgrade them, stop the waves.
Tusk	action, rpg, roguelike	An action-RPG rogue-like (and a nod to the pink elephant this whole site is named for). Fight, collect powerful abilities, die, and start over smarter. Each run is different — dying is the learning.
Typing	keyboard, wpm, speed	A typing game set in space: hit the words to shoot.
Shape War	rts, real-time, tactics	Real-time strategy played entirely with shapes.
Trunk Line	rts, tactics, ai	A 1v1 real-time strategy match on a single screen. Both sides get the identical 45 soldiers — 10 shields, 10 pikes, 15 archers, 10 cavalry — so the AI wins on decisions, never on stats. Hold the camp in the middle until your bar fills. The non-obvious part: every order lands late on purpose. Turning costs time, switching stance costs time, and a charging horse cannot steer, so a lane that clips your own line flattens your own line. Friendly fire counts for both sides, and the end screen tells you how many of your own men you shot. Four AI difficulties — press D to watch the hardest one think.

Puzzle & brain

Slower games. Each one trains a specific muscle.

App	Keywords	What it is, and the non-obvious part
100 Pirates	logic, riddles, brain teaser	Classic logic riddles — pirates splitting gold, prisoners and hats, the light-bulb puzzle. Perfect for a car ride with kids. Each one trains the same move: reason backward from the end.
24	math, mental math, kids	Make 24 from four numbers using +, −, ×, ÷ and brackets. The mental-math game I’d hand a kid — it drills arithmetic and order-of-operations and never feels like homework.
2048	tiles, merge, ai	Slide tiles to merge up to 2048 — or watch a trained neural-network AI beat it. The AI hands you the winning human rule: pin your biggest tile in one corner and never move it.
Minesweeper	probability, solver, logic	Classic Minesweeper, solved by an algorithm.
Recall	memory, pattern, brain	See a pattern, then reproduce it from memory. A working-memory trainer that grows the pattern until you break.
Sudoku	puzzle, logic, numbers	Standard Sudoku. Clean, no ads, plays fine on a phone.
Concentration	words, memory, party	Name words that fit a theme, round after round. A memory-and-vocabulary game.

Simulations, physics & science

Toys that are secretly lessons. Push them and watch a real idea appear.

App	Keywords	What it is, and the non-obvious part
4D Slices	fourth dimension, geometry, math	A four-dimensional solid, shown as the 3D slice you’d actually see. The same way a flat shadow stands in for a solid object — it’s the closest a three-dimensional brain gets to seeing 4D.
Black hole	gravity, event horizon, space	A black-hole simulation — watch gravity bend things around the event horizon.
Flock Simulation	boids, swarm, emergent	Boids: hundreds of birds flocking from three simple rules. The lesson lands on its own — complex group behavior needs no leader, just local rules. Drag to scatter them.
Fluid Simulation	water, dynamics, interactive	Push water with your mouse and watch it swirl. Real fluid dynamics underneath.
Fourier Epicycles	math, circles, waves	Draw anything, and stacked spinning circles redraw it. The clearest picture of what a Fourier transform does: any shape is a sum of circles.
Hydrogen Orbitals	quantum, atom, schrödinger	The real solutions to the Schrödinger equation for a hydrogen atom. Change n, ℓ, and m and the shapes change with them. The lesson that surprised me: an electron isn’t a dot circling a nucleus, it’s a cloud of probability.
Particle simulator	particles, effects, art	A particle playground — spawn them, push them, mix them, watch the attraction and repulsion.
Pendulum	single pendulum, chaos	Try to balance a single pendulum.
Rolling Coins	coin rotation paradox, geometry	Roll a coin all the way around another coin the same size. How many times does it spin? Everyone says once. The answer is twice. Predict first, then watch — every count is split into rolling plus bend, so you can see where the extra spin comes from. This exact question was on the 1982 SAT, and every offered answer was wrong.
Sand	falling sand, cellular automata	Falling-sand physics: drop sand, water, and other materials and watch them interact. Simple rules per pixel, surprising results.
Water	pid, control theory	Tune a controller to hold a water level steady. Quietly educational — it’s control theory, the same math behind a thermostat and cruise control, played as a game.
Chance Lab	probability, dice, monte carlo	A hands-on lab for probability — dice, coin flips, rare “black swan” events. Run enough trials to feel how randomness behaves. Pairs with Turkey below.

Space & astronomy

App	Keywords	What it is, and the non-obvious part
Astro Facts	astronomy, facts, education	Bite-size astronomy facts and celestial data. A quick way to hand a curious kid something true and full of wonder.
Astro Globe	earth, seasons, 3d	A 3D globe showing why we have days and seasons. “Why is it cold in winter?” answered by seeing the tilt, not reading about it.
Earth	globe, geology, cutaway	The Blue Marble, and you can spin it — drifting clouds, sun glinting off the ocean, city lights on the night side. Press C and a quarter of the planet swings open into the textbook cross-section: crust, mantle, outer core, inner core, at true scale. Every layer except the crust. At true scale the crust is thinner than one pixel.
Galaxy Collision	galaxies, tidal forces, simulation	Two galaxies crash into each other, 146,000 stars at a time. Hundreds of millions of years compressed into a minute — and almost no stars ever hit. Space is that empty.
Night Sky	constellations, stargazing, map	A star map — find the planets overhead. Check it before you head out to stargaze.
Scale Navigator	scale, zoom, cosmos	Zoom from the Planck length to the whole universe in one scroll. Nothing resets your sense of scale like going atoms-to-galaxies without stopping.
Solaris	solar system, 3d, orbits	The solar system in 3D, with orbits. Fly out and feel how empty space really is — the planets are tiny and far apart.
The Sun	star, fusion, photosphere	Earth’s twin, for a star. Spin it, then cut it open: convective zone, radiative zone, and a core fusing 600 million tons of hydrogen every second. The number that lands is on the surface, though — the photosphere boils at 5,772 K, and each bubble in it is about the size of Texas.

Thinking labs & big ideas

The apps I care about most. Each one packages a hard, useful idea into something you can play with.

App	Keywords	What it is, and the non-obvious part
Game Lab	game theory, nash, strategy	An interactive intro to game theory — Nash equilibrium, the game of chicken, cooperate-or-defect. Play the games with a group and feel why “rational” players can all still lose.
Mind Lab	system 1, system 2, bias	A tour of fast (gut) vs. slow (deliberate) thinking, with tests that catch your own blind spots. It’s best when it fools you — that’s the whole point.
Logic Lab	arguments, fallacies, reasoning	How to build an argument and how to test one — valid, sound, strong, and the classic ways reasoning fails. Exercises, not reading. Pair it with Mind Lab: one shows how you get fooled, this one shows how to check.
Influence Lab	persuasion, scarcity, authority	The seven levers of persuasion — reciprocity, scarcity, authority, social proof, liking, commitment, and group pressure — shown being used and defused. Learn them once and you’ll spot every ad and salesperson pulling them.
NVC Lab	non-violent, conflict, empathy	A trainer for nonviolent communication: separate observation, feeling, need, and request. The hardest and most useful of the labs — it retrains how you handle conflict at home and work.
So What	nihilism, meaning, philosophy	A short, gentle sit with the “so what does any of it matter?” question — faced instead of dodged.
Turkey	induction, black swan, why	The turkey who asks “why” — a tiny retelling of the problem of induction. Every day the farmer feeds the turkey, so the turkey concludes farmers love turkeys. Until Thanksgiving. Past data can’t prove the future.
Rocky	project hail mary, sci-fi, 3d	Meet Rocky, the Eridian from Project Hail Mary, in 3D. A love letter to the book. If you’ve read it, you already hear his voice.

Book companions

The newest group, and the one I use most. I read a book that changes how I think, and the notes fade in a month. So now I build the book a companion: the core ideas, in order, that I can open in thirty seconds a year later. They don’t replace the book. They keep it from evaporating.

App	Keywords	What it is, and the non-obvious part
Diary of a CEO	business, life, 33 laws	Steven Bartlett’s 33 laws of business and life, sorted into four pillars. The book behind the table everything sits on — that image came from here.
Why We Sleep	sleep, circadian, health	Matthew Walker’s book: what sleep is, what it does, what ruins it, how to get more. The evidence under waking on the first alarm. Read it once and you stop treating sleep as the thing you cut.
No-Drama Discipline	parenting, regulate, whole-brain	Siegel and Bryson on discipline as teaching, not punishment. Connect first, redirect second — the idea I put at the top of my lessons. The one app I wish I’d had earlier.
The Almanack of Naval Ravikant	wealth, happiness, leverage	Naval’s collected thinking, split into wealth and happiness. His claim is the useful one: both are learnable skills, not luck. Sits beside where capital comes from.
On Tyranny	history, politics, resistance	Timothy Snyder’s twenty lessons from the twentieth century, each one short. History as a warning you can read in ten minutes.
A Brief History of Intelligence	evolution, brain, ai	Max Bennett’s five breakthroughs that built human intelligence, each with something to do. It runs the parallel to AI the whole way, so you learn brains and machines together.
Reality Is Not What It Seems	quantum gravity, physics, rovelli	Carlo Rovelli on quantum gravity. The best part isn’t the physics — it’s that every idea is labeled by how settled it is, from confirmed to speculative. More books should mark their own edges that way.
Ethnic America	sowell, immigration, history	Thomas Sowell’s history of nine groups — Irish, German, Jewish, Italian, Chinese, Japanese, Black, Puerto Rican, Mexican — one screen each, with his measurement traps as things you can move. The first one sets up the book: sort the groups by income, then sort them by median age, and you get nearly the same list in nearly the same order. Sowell’s ending is deliberately unsatisfying — no single explanation survives all nine groups.
Making Sense	sam harris, consciousness, ai	Not a book Sam Harris wrote — a book he hosted: edited podcast conversations with Chalmers, Seth, Metzinger, Sapolsky, Kahneman, Bostrom, Krakauer, Tegmark, and Deutsch. Each one is something to do rather than a summary to read: draw from Bostrom’s urn, run Seth’s controlled hallucination, zoom Sapolsky’s stack of causes, test Deutsch’s rule that a good explanation is hard to vary. The guests disagree with each other, and the app keeps the disagreements instead of smoothing them.

Learning & languages

App	Keywords	What it is, and the non-obvious part
Chicken Bunny	counting, kids, math	Counting and early math dressed up as chickens and bunnies. Built for the youngest learners.
Multiplication Mania	times tables, kids, quiz	Times-tables as a quiz game with voice input. The one drill I actually want a kid to repeat — fluency in the tables makes all later math easier.
Study in Germany	german, everyday, students	Duolingo teaches you words. This teaches the sentences you actually need this week: ordering in the Mensa while eleven people wait behind you, losing the race at the supermarket checkout, decoding the station loudspeaker before everyone else moves, emailing a professor without sounding like a robot or a child. There’s a working DB ticket machine to practice on.
Präpositionen	german, grammar, mnemonics	German prepositions and word order, as pictures you click instead of tables you memorize. Each case gets one absurd image you can’t unsee. Accusative is the number 40: vier sounds like für, the 0 is ohne, and an arrow goes durch the zero. Dative is a house standing seit 1900. Sentence order is a teapot with a spoon in it — Te-Ka-Mo-Lo. Written in German, built for my own. The ridiculous pictures stick; the grammar tables never did.

Everyday calculators & utilities

The tools I built because I needed them and didn’t want the ad-covered version.

App	Keywords	What it is, and the non-obvious part
Date Counter	days, duration, countdown	Days between any two dates — for “how long until…” and “how long since…”.
Day of Year	day number, calendar	Which day number (1–365) today is. Handy for planning and journaling.
Death Clock	life expectancy, longevity	A rough life-expectancy estimate from lifestyle answers. A nudge, not a prophecy — it puts a number on why health is the table everything sits on.
Inflation	purchasing power, cpi, dollar	What a dollar bought then versus now. Shows that “prices used to be so low” is mostly inflation, not a lost golden age. Pairs with the money tree.
Fire	financial independence, retirement	A financial-independence / retire-early calculator: it projects your net worth to the year you could stop working. The tool behind how much is enough — import/export your settings and print the report.
Split Bill	bill, tip, friends	Split a check among friends, tip included. Ends the “who owes what” math at dinner.
Temperature	celsius, fahrenheit, kelvin	Convert °F / °C / K.
Timezones	world clock, meeting, travel	Convert a time across cities — for scheduling a call or planning a trip.
Text Converter	case, format, camelcase	Change text case and format — uppercase, lowercase, camelCase. A small thing I reach for constantly when writing or coding.
Word Counter	characters, writing, essay	Live word and character count as you type. For anything with a length limit.
Working Day Counter	business days, deadline	Business days between two dates, skipping weekends. For deadlines and leave planning.
Todo	tasks, checklist, simple	A very simple task list. No account, no sync, no extras.
Redo	recurring, habits, routine	A recurring to-do list — tasks that come back daily or weekly. This is the one behind waking on the first alarm: the point is habits, not one-off chores.
Scan	pdf, document, camera	Photograph a document and get a clean multi-page PDF. It finds the page edges, flattens the perspective, and evens out the lighting. The part that matters is where it runs: every pixel is processed by your own browser. There is no server to upload to, so a passport or a tax form never leaves your phone.
QR Peek	qr code, phishing, privacy	Paste a screenshot of a QR code and read the link before you visit it. The host is shown in full weight and everything else is dimmed, so `apple.com.evil.ru/login` reads wrong at a glance. It names the tricks too: a username before an `@` that hides the real host, a punycode domain that renders as ordinary letters, a `javascript:` payload that is code rather than an address, a swapped payment QR. Short links are deliberately not expanded — following a bit.ly to find its destination would mean handing your link to someone else’s server, which is the one thing this page promises not to do. Nothing is uploaded, and nothing opens without your click. Pairs with Scan above.
White Board	drawing, sketch, canvas	A blank canvas to draw and think on. Opens instantly when a picture explains it faster than words.
Coupon Codes	discount, deals, savings	A place to find and share discount codes before checkout. Two minutes here often beats the “sale” price.
RainCheck	lawn, watering, weather	Should you water the lawn today? It checks the recent rain and tells you. Built because I kept watering grass the sky had already watered.
Random Tools	dice, lottery, teams	Roll dice, run a lottery, shuffle people into groups. My first choice for settling arguments and picking fair teams.
Zodiac Sign	chinese zodiac, birth year	Your Chinese zodiac animal from your birth year.
Exercise	fitness, workout, tracker	A daily workout tracker you write in plain markdown, with a built-in timer. The app behind my ideal day — download and upload your routine as a file, so it’s yours, not locked in.

Party & group games

Made for a room full of people. Everyone plays; no one sits out as narrator.

App	Keywords	What it is, and the non-obvious part
Ice breakers	penguin, questions, social	Don’t let the Penguin fall!
Werewolf	mafia, moderator, social deduction	A facilitator for Werewolf / Mafia — it runs the night phase so nobody has to sit out as the narrator. Gather people; the app moderates.
Trunk Party	multiplayer, fast math, odd one out	A fast multiplayer showdown — quick math, quick reactions, odd-one-out hunting. Everyone plays on their own phone.
NLTH Dealer	poker, texas holdem, chips	A virtual chip tracker for a home poker game. Play with real friends, skip the physical chips and the counting.

Food, life & culture

App	Keywords	What it is, and the non-obvious part
Chinese Food	recipes, cuisine, authentic	A guide to ordering Chinese dishes at restaurants.
Sous Vide	temperature, steak, guide	Times and temperatures for sous-vide cooking. The reference I actually check before dropping a steak in the bath.
Cat	virtual pet, kitten, kids	A simulated cat to care for. A gentle virtual pet for a kid who wants the real thing.
Shanghai Dialect	shanghainese, language, culture	Learn Shanghainese phrases and pronunciation.
Past	history, on this day, timeline	All the way to the beginning of the universe.

Reading & writing

App	Keywords	What it is, and the non-obvious part
About	blog, essays, notes	This blog — essays and notes, written to be read slowly. You’re on it now. Searchable, cross-linked, no ads.
Offline Book	reader, ebook, offline	A book reader that works with no internet. For flights and dead zones.