Every cell holds one half-square triangle turned to one of four orientations. Near the top they lock into pinwheels, arranged so that no two dark triangles ever meet along a straight edge — which is what keeps the grey perfectly even. Further down an increasing share of cells abandons the rule, edges begin to fuse, and the field clots into irregular clusters. The transition is the subject: the same vocabulary reads as texture and as noise depending only on where you look.
Related Patterns
