Crevasse Field

Crevasses three to seven cells wide in a wind-scoured ice sheet, for trying rope bridges of every span.

Concepts

Hook Approved

Crevasses three to seven cells wide in a wind-scoured ice sheet, for trying rope bridges of every span.

Premise Approved

A home for one sagging rope swing bridge, added by a later prompt, and for trying short and long spans of it under engine 0001's bridge rules (GAMEPLAY.md → Bridges, with the gameplay.json defaults: reach 24, setback 12, grade at most 12°, no maxSpan). The map is 24×20 cells (576×480 units), north up, seen from the south. Two crevasses run north–south, so a bridge across either runs east–west, side-on to the opening camera. The west crevasse is 3–4 cells wide (72–96 units) and about 260–290 units deep; it runs off the south edge and closes about 7 cells short of the north edge, so both crevasses widen toward the camera. The east crevasse is 5–7 cells wide (120–168 units) and about 335–385 deep, and runs off both edges; their walls converge downward to a floor one cell wide or a V. (The first brief asked 60–100 deep; at the terrain review the user chose four times that.) Each changes width in whole-cell steps, so every width from 3 to 7 has a straight reach at least 3 cells long to bridge: 96–192 units landing to landing. A strip of ice 4–5 cells wide between them lets two bridges chain. Along a bridgeable reach the wall follows a grid axis, so the lip is one straight tile edge. The lip is rounded and falls away from the landing half a cell behind it, so no ground rises between the two landings (the engine allows 1.2 units) and no snow cornice or drift ridge stands on a lip; the two landings stay well inside the engine's 12° grade (under 3° in practice). The engine checks no ground behind a landing, so the surface beyond the lip may be lumpy. Crevasse walls and floors are their own unwalkable tiles, which the bridge will cross; every surface tile is a walkable landing. A dwelling is 20 units, so the crevasses are 13–19 dwellings deep.

Environment Approved

The flat top of an ice sheet just upstream of where it drains into an outlet glacier past the east edge. The ice flows east and speeds up over a buried bedrock rise, and its brittle upper layer pulls apart into transverse crevasses that run north–south, across the flow, wider downstream where the stretching is greater. Crevasses grow as segments that link en echelon, so a wall steps sideways where two segments joined. Their walls show white firn over banded blue glacier ice that deepens to glowing blue in the depths; their floors are choked with fallen snow and ice blocks in deep shadow. A katabatic wind pouring east off the ice sheet scours the surface: long patches of bare, glassy blue ice, hard wind-packed snow cut into sastrugi ridges, and soft drift in sheltered lees. One medial moraine, a dark stripe of rock debris carried on the ice from a nunatak far upstream, runs east with the flow and across both crevasses, leaving boulders and glacier tables (boulders on ice pedestals). No plants and no liquid water. A low polar sun from the west-southwest throws long shadows, with warm light on the snow against blue shadow in the crevasses; the sky is pale and cold. Desolate, silent and vertiginous.