7 Most Satisfying Physics Simulations (One Heart Bounced Until 2,048 Hearts Filled It) 🌈

About this piece

Photosensitivity: no full-screen flashes (measured frame by frame). Small patches, at most 13 of about 1,300 screen cells (1% of the screen), flicker briefly in the triangle chapter at 0:52-1:15 and as the room of splitting balls fills at 2:37-2:44.
One heart bounces inside a big heart. Every time it hits the wall, every heart in the arena gets a twin: 1 becomes 2, then 4, 8, 16, and so on. Eleven bounces later there are 2,048 hearts, and they glide into a lattice that fills the heart in 12 rainbow columns, while the counter beside the picture climbs from 1 to 2,048 hearts in about 38 seconds.

Six more rules follow, each running to its end. A triangle bounces around a square room and grows one more side at every bounce, until after 61 bounces it has 64 sides, each in its own colour. One line follows the Gosper curve through 2,401 hexagons, visits every one exactly once without crossing itself, and leaves a rainbow island. A ball in a square room splits into 3 at every wall hit, until after seven generations 2,187 balls leave no room and settle into rainbow rows. A 15 by 15 grid with no black squares fills one word at a time, until 225 letters in 50 words cover every cell. 1,128 small paper triangles fold open one at a time, each from the edge of a neighbour, until they fill a Koch snowflake. Last, 42 red and yellow discs drop into a 7 by 6 board in turn, until the board is a checkerboard.

No talking. The number beside each picture is the simulation's own count at that moment, and each chapter shows its rule on screen and runs without cuts.

What is real and what is planned? In the heart, the lead heart reflects off the curved wall and the other hearts collide with each other as discs, computed frame by frame; the lead heart's speed is steered so each bounce lands on time, and the last step is a two-second glide onto the lattice. In the square room the balls bounce off the walls for real. The curves, the word grid, the paper folds and the board follow their rules, not physics. The rules, the code and the sound are all original.