A flat crease-pattern net of an octahedron reads as a 2D technical drawing — paper-toned facets with glowing fold lines. The fold lines pulse in sequence, then the eight triangles fold up hinge by hinge along a parent→child hinge tree, staggered eased rotations accumulating down the tree into the finished polyhedron, which rotates slowly as a real solid before unfolding back to the flat net. The net layout and per-hinge fold angles are solved at init by numerically unfolding the folded solid, and double-sided faces show a distinct back-paper tint as the backs turn to the camera mid-fold. On the sketch’s own page, drag to turn the paper in hand — even the flat net — and it springs back on release.