A dilation stretches or shrinks a figure from a center by a scale factor k: every length is multiplied by k, and from the origin every coordinate is too, (x, y) to (kx, ky). Two figures are similar when a sequence of slides, flips, turns and a dilation lands one on the other. Matching angles are equal and matching sides share one ratio, so a missing side comes from the scale factor. Two equal angles are enough to make two triangles similar. The crew enlarges cutouts with a flashlight shadow at the Blueprint Table.