NXT Lab · Simulations

Simulations.

Small simulations with simple rules. Watch what the rules do.

A cave map filled with coloured balls
1. Bounce & spawn Two balls bounce in a circle, square, triangle or random cave. Every collision spawns a new ball. How long until it is full?
Space-time diagram with red braking waves travelling backwards
2. Traffic waves Identical drivers on a ring road, each reacting a moment late. Tap the brakes once and watch a jam grow, or fade, behind you.
Towns of stick figures, some red with the virus, joined by roads
3. Virus spread People in towns, a few travelling between them. Set how contagious the virus is, then try lockdown, quarantine, masks and vaccines.
A grid of blue and orange smiling faces split into separate areas
4. Segregation Each person only wants a few neighbours like them, yet the town splits apart. Schelling's famous model, with every tolerance compared at once.
A murmuration of starlings, a dark cloud of birds against a peach evening sky over the Alps
5. Bird flock Two thousand starlings over the Alps in 3D. Each watches only its 7 nearest neighbours and reacts a moment late. Then a falcon stoops.
A candlestick price chart with a sudden crash while the fair value line stays flat
6. Order book market Random traders, market makers, trend followers, value traders and whales share one order book. No news, yet the price crashes. Be the whale.
Streets of an old town with queues of cars and trucks at traffic lights
7. City traffic Cars, vans, buses and trucks cross an old town, each the quickest way. You run the lights: fixed, sensors, three smart rules, or by hand.
Yellow balls bouncing down a triangle of pegs into buckets that form a bell curve
8. Galton board Every ball flips a coin at every peg. Nobody can say where one lands, yet thousands always build the same bell-shaped hill.
A green forest seen from above with a ring of orange fire burning through it, leaving grey ash
9. Forest fire Trees grow, lightning strikes, fire spreads. Most fires are tiny, a few burn half the forest. Cut firebreaks, thin it, or send firefighters.
Rule 30: a triangle of white and black cells, orderly on the left and chaotic on the right
10. Tiny rules Wolfram's 256 one-line rules. Rule 30 makes chaos, rule 90 a fractal, rule 110 a computer. Emergence, no shortcuts, Turing completeness.
A green field with white rabbits and orange foxes, patches of grass eaten down to brown earth
11. Rabbits and foxes Rabbits eat grass, foxes eat rabbits. The numbers rise and fall in waves, foxes always late. Too much food crashes it; shooting rabbits makes more.
Ants on glowing blue and orange scent trails winding between grey rocks from a nest to two green food piles
12. Ant trails No ant knows the way, each only smells the ground ahead. Together they find the shortest road to the food. Block it and they find another.
Glider guns firing streams of gliders that cross and cancel, with lamps showing NOT, AND, OR
13. Game of Life Conway's three rules. Gliders, guns that fire them, logic gates made of crashing gliders, and a working Turing machine.
A town of coin piles: a few huge golden and orange piles among many tiny dots
14. Yard sale Everyone starts equal and trades on fair coin flips, yet a few end up with almost everything. See why, and how much tax it takes to stop it.
A grid of coloured squares: who scores what against whom in a prisoner's dilemma tournament
15. Cooperation 25 strategies play the repeated prisoner's dilemma, as in Axelrod's tournaments. Tit for Tat never wins a match yet beats Always defect. Then evolution, mistakes and secret endings.