Wrapped Pattern

a printed sheet that rolls into a column. flat it is a drawing, wrapped it turns under a drag, coasts when let go and idles on a slow turn.

key insight: the roll is a bend, not seventy-two strips turning about their own centres, which tears the print into ragged verticals on the way. the sheet lies on a cylinder whose radius closes from infinite to R, so at every point the strips still lie edge to edge on one curved surface.

two numbers drive everything and nothing renders. --t and --rot are written to the scene once a frame and every strip's transform, its shade and the shadow's width are calc() off them.