9. To verify this, you can make a drawing of a cube, &
number each of its 12 edges. Then, always starting from 1 corner & 1 edge,
you can determine all of the possible paths for tracing along the edges
of a cube. There is no need to start from other corners or edges of the cube, as
you will only be repeating the same paths. The process is a little more
involved than this, but is useful for solving many types of spatial and logical puzzles.