一颗行星缓慢运转的机理。

Erupt a volcano into being and watch its silhouette — broad shield or steep stratocone — fall straight out of its magma’s viscosity and gas.

Watch a river snake across its floodplain — bends grow where the current bites the outer bank, until a neck pinches shut and an oxbow lake is born.

Drag drifting plates to raise mountains, tear open rifts, and unleash earthquake blooms along living boundaries.

A box of rock heated from the core and chilled at the surface — buoyant plumes rise, slabs sink, and convection cells spread the plates above them.

Pour a river of ice down a V-cut valley and watch it grind the bedrock into the broad U-shape, cirques, and fjords that ice leaves behind.

Loose a million raindrops on a fractal mountain and watch them carve river valleys and braid ridgelines into existence.

Blow wind across a sheet of sand and watch ripples and crescent dunes self-organize out of nothing but slabs hopping downwind.