A geometric cartoon of pattern formation: convection cells appear underground, compete for space, and their shared boundaries become the salt ridges visible at the surface.
Cell centre: fresher brine rises here
Claimed region: one convection cell
Brown lines: salty brine sinks, ridge grows
Relaxation: cells even out toward hexagons
Step 1
Convection cells appear
Small differences in the brine layer seed separate overturning cells beneath the crust.