Can you work out the dimensions of the three cubes?
Here is a proof of Euler's formula in the plane and on a sphere together with projects to explore cases of the formula for a polygon with holes, for the torus and other solids with holes and the relationship between Euler's formula and angle deficiency of polyhedra.
60 pieces and a challenge. What can you make and how many of the
pieces can you use creating skeleton polyhedra?
Published November 2009,October 2009,December 2011,February 2011.