A 2D pond of soft-bodied creatures built from grid cells (core, bone, muscle, cartilage, eye). They swim in continuous space, hunt food and each other, and evolve body and brain with no fitness function: a creature that banks enough energy buds off a mutated child, and one that runs out dies.
pixi run serve # http://localhost:8000
pixi run check # headless regression checks (~20 s)Options for serve: --port, --seed (reproducible world), --pop (starting
population), --seeds eel,tadpole (which built-in seeds), --genome saved.json (start
from a genome exported with the viewer's Genome JSON button).
Without pixi: pip install -r requirements.txt, then python server.py.
Viewer: click a creature to follow it and see its body map and live brain. Drag to pan, scroll to zoom, double-click to drop food, space to pause.
- Bodies: each cell is a square of 4 point masses joined by springs, and neighbours share corners. Muscles contract 50% along an evolved axis. Drag acts on leading faces only, so undulation produces thrust. A small evolved net (a CPPN) paints the body.
- Eyes: clusters of eye cells see RGB light from food, other creatures and the walls, with range proportional to cluster size.
- Brain: a sparse NEAT-style CTRNN in the core, with evolved Hebbian plasticity and reward neuromodulation. Sensors and motors bind to nearby cells, so the brain survives body changes.
- Ecology: steady-state reproduction, food hotspots, a soft population target, and predation by creatures more than twice the prey's size.
- docs/ARCHITECTURE.md: design, parameters, and what failed.
- CLAUDE.md: orientation for AI assistants (invariants, status, roadmap).