2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/115191We give a simple proof of the following result: There exists a non-convex polyhedron whose surface is isometric to the surface of a cube of smaller volume.3 pages, 2 color figuresMetric GeometryCombinatorics52C25; 52B10; 52B60text