When a polyhedron is unfolded to make a net, the way that the edges were linked up requires some spacial thinking. This Demonstration provides a simple space visualization test using edge identification. Each triangle has one side (the thick one) that is an edge of the polyhedron, and the number in the triangle labels this edge.

The cube has 11 different nets. Each edge is adjacent to two faces. We number the edges and display these numbers by triangulating the faces and putting the edge-numberings into the adjoining triangles.