Blintz Base Fold — Origami Simulation

This simulator builds the origami blintz base from real crease-pattern geometry: a square sheet whose four corners each fold to the center along the perpendicular-bisector crease that naturally connects two adjacent edge midpoints. Every corner is animated as a true hinge rotation about its own crease line, computed with Rodrigues' rotation formula, so the corner point traces a physically exact arc and lands exactly on the center at a 180° fold — not a scripted shape morph. Drag the fold-progress slider or hit play to watch the sequence unfold one corner at a time, and see how the four folded triangles exactly tile the remaining diamond with no gaps or overlaps, stacking five layers of paper at the center.