World builder 01
Random world size range Minimum side Maximum side
Generate a world chooses an integer side length in this range. In 3D it also sets depth. These limits do not resize the current world.
Starting templateThe cooperative tidepool Predator arms race The multicellular frontier Tragedy of the commons Islands & isolation Resource patches reward nearby cells that invest in cooperation.
One shared engine. The buttons above load editable starting values. Every world supports all the mechanisms below.
World width & height 256 × 256 64–2,048 units per side. Changes the actual habitat, independently of zoom. 3D uses this depth too.
Resize living world Keeps time, organisms, and bonds. Repositions intact assemblies; stretches resource regions, signals, and remembered locations. Shrinking increases crowding. Stop timed experiments before resizing.
SubstrateContinuous 2D 3D volume TerrainNutrient archipelago Open commons Sparse resource vents Divided habitat World seed Initial units
Reproduction & gradual isolation Sexual reproduction preference Compatibility breadth Recessive health cost Sexual attempts need a partner encountered at physical contact within 300 ticks. Genetic divergence smoothly reduces fertilization. Shared recessive variants can reduce offspring viability and adult health. At 100% sexual reproduction, isolated founders can fail to establish.
Breeding-group display threshold This threshold classifies the diagnostic groups only. It never blocks mating.
Evolving behavior circuits Inherited circuit influence Structural mutation share Circuit energy cost Each creature inherits a smooth recurrent circuit. Mutations alter weights, timing, connections, and nodes. Influence 0 removes its behavioral effect; 100 gives it full control of directed steering. Global mutation probability also controls circuit mutation. Apply dynamics to change these live.
Initial foundersMixed founders Cooperators Grazers Predators Colony builders Memory & nested systems
CommunicationContact + broadcasts + traces Contact and bonded relays Broadcasts within sensing range Persistent environmental traces No communication
Memory slots Precision (bits)
Maximum new nesting depth Capacity, retention, learning, transmission, and trust also vary through inherited traits. Copying an assembly costs stored energy and shares its body mass.
Regional conditionsTemperature, moisture & pressure mosaic Uniform conditions All units inherit regional tolerances. Color the world by conditions in the View menu.
Shared behavior mix Sensing distance 10 units Signal persistence 88% Heading alignment 95% Change these strengths independently. No template locks a behavior. Zero disables a contribution; inherited traits vary the response between units.
Trail following Neighbor attraction Anchoring Attached budding Contact assembly Maintenance cost Regional resource drift Energy sources & ecological pressures Uniform / solar input Localized thermal vents Chemical bands & pulses Sources combine into locally harvestable energy. Renewable energy input scales all three; zero stops outside input. Apply dynamics to change sources live. Start with Grazer founders to test the evolution of feeding on other organisms.
Mutation probability 8% Renewable energy input 55% Cooperative benefit 60% Predation pressure 35% Season length (ticks) 0 disables seasons; regional drift is independent.
Population ceiling Apply dynamics without resetting Keeps organisms, memories, and history. Use Resize living world to change its size. Substrate, terrain, initial population, population ceiling, founder type, and seed change only when creating a new world.
Create & run world Creates a fresh experiment with every setting above. Save first to keep this world.
TICK 0 100 × 100 UNITS
Click to inspect · choose Seed to introduce cells ↻ Rotate
Growing a world…
Scattered founders → local interactions → structure New world
▶ Run Step +1 Speed1× 5× 20× Maximum CPU workers1 2 4 8 Paused
Motion is interpolated between simulation updates; physics remains exact. Nested outlines: connected assemblies · cyan contours: stored traces · violet pulses: record transfers · gold pulses: shared energy. Use Information view or zoom in for detail.
Run experiments across CPU cores 1 worker is often fastest for smaller habitats; 2–8 distribute spatial searches. More threads do not guarantee higher ticks/s. Independent worlds run concurrently from the current world’s confirmed rules, using different seeds. Your habitat keeps its state. Uses the timed-run duration.
Concurrent experiments2 4 8 Run parallel experiments Compare separate evolutionary histories in Run results.
Breeding populations Estimated, not fixed species labels
Watch the world change Actual snapshots · first and three most recent
Life over time Population · sampled each 25 ticks