Simulation controls

The bar above the workspace controls the running simulation.

Setup - re-initialise the world. Runs every setup_rules, sets the tick counter to 0, and re-seeds the RNG from Seed.
← Step - replay one tick earlier. Only works while time-travel history is valid (i.e. you haven't made a structural edit since the last Setup).
Step → - run one tick forward.
Go / Pause - run forward continuously until paused.
Tick / Agents / Seed - live counters. Click the seed number to edit it or hit ↻ to randomise. Either action re-runs Setup.
Undo - pop the last structural edit (add/update/delete on an agent type, rule, property, etc.). Doesn't affect ticks or slider changes.

Time travel

Every Setup starts a fresh history. Stepping forward records checkpoints; ← Step replays from the nearest checkpoint forward to tick - 1. Any structural edit (changing a rule, adding an agent type) invalidates the history - the back button greys out until your next Setup.