What problem does it solve? It documents how elevation steps between terrace levels work in the procedurally generated overworld, so changes to walkability, ground placement, or board rendering stay consistent with the cliff rules. ## Core Features & Use Cases - Cliff detection rules: Defines how levelAt and isFace identify cliff cells, including diagonal neighbours and 2x2 block constraints. - Seam and pass logic: Explains when water, roads, routes, and natural passes cut through cliffs, and when a face stays unwalkable. - Rendering guidance: Describes how both the flat board and the laid-back board draw cliff tiles using the biome's face terrain autotile. - Use Case: When adding a new landmark placement rule, consult this Skill to exclude face cells via Chunk.getFaceCells() so nothing spawns on a cliff. ## Quick Start Ask how terrace levels and cliff tiles work before changing walkability, ground placement, or board drawing code in the overworld.