The land

A valley without the town, run forward by years under a climate scenario: height, change, snow and ice, fertility, water.

This is the engine's playground (G → playground in the viewer, or cargo land-probe headless): a valley raised from a recipe with no town on it, run forward under a climate scenario. Snow lies as voxels, firn turns to glacier ice that creeps downhill, meltwater feeds the rivers, fertility follows, and a feature can be carved into it live. Every reading in the timeline is a Frame from crates/engine/src/playground.rs.