the playground

Four rules, no controller, and structure that keeps arriving anyway. It's the reason 'emergence' is my favorite word in computer science. Draw on the grid to interfere.

Two searches, one maze, same shortest path. Dijkstra floods politely in every direction; A* has a heuristic and a hunch. Draw walls to ruin their day, then watch the pop counters. That gap is what 'informed search' means.

Three rules per bird and nobody in charge, and the flock organizes itself anyway. Your cursor is the hawk; press the button to become breadcrumbs instead.

Sand falls, water finds the gaps, stone ignores you. A physics engine in one byte per pixel. Paint something and let gravity do the code review.

Two chemicals, one feeding and one killing. Paint a drop and watch Turing patterns breed across the grid, the same math nature uses for leopard spots and seashells. Tap pattern to switch between coral, mitosis, and maze.

The Navier–Stokes equations solved on a grid sixty times a second, using Jos Stam's 'stable fluids' method, the same trick behind every movie smoke shot. Move through it and stir. The swirls are the math refusing to settle.

Newton's law, every body against every other. Drag anywhere to sling a new planet. The dotted line is its future, right up until the other planets get a vote. An orbit is just falling and missing.

Every physics game you rage-quit on a 2010 iPhone, distilled down. Pull the sling, loose the shot, watch the crates argue with Newton. The green tins are the point: clear the wave in as few shots as you can.