Water and lava that flow, down through the layers and over the edge
Liquid runs now. Pour a lake out of a storage ring at the top of a shaft and it goes down, layer by layer, and fills the room at the bottom. Dig beside a pool and it drains into your hole. Flood an ant nest and the ants drown. Lava creeps, burns what it touches, and turns to black glass where it meets water.
- Every cell holds up to seven units of a liquid, and its glyph and colour show how deep: shallows, water over your head, deep water.
- One rule moves it all: down through any floor that lets it (a hole, stairs, a grate), then out toward level, then still. A grate lets water through; glass holds a pool over a room, until it breaks.
- Pools, rivers and lakes sit in their beds until you disturb them. Dig beside one and it runs into your hole; take it into a ring and its bed is left dry. A spring fills itself again.
- Water over a creature's head drowns it if it breathes and can't swim, after a breath or two, and you're told. People, wolves, dogs and bears swim; ants don't. Creatures make for dry ground when it rises round them, and nothing walks into water over its head it can't swim, or into lava.
- Lava moves every few turns, glows, burns through a wooden floor and comes down after it, and kills what it touches unless it resists fire. Where it meets water it sets as black glass in a burst of steam. It lies in the deepest caves.
- A ring or bag holds the very units it took in, and pours them back out to flow. Holding lava hurts it every turn, less the higher its grade, until it burns through.
- Liquid runs off the edge of a map into the next stretch of country, above ground or below, and arrives there when you next go.