Problem of the week: Tetrahedron Puzzle

I was reading through Martin Gardener's book Origami, Eleusis, and the Soma Cube where he described a plastic math puzzle consisting of two pieces that you have to put together to form a tetrahedron and thought it sounded like fun.  He kindly gives a pattern so one may be cut out of paper:

Your challenge is to print out two of these patterns on thick paper, make the pieces and put them together to make a tetrahedron.  

A pdf of the pattern is available here.

By Jim Town - Mathematics Specialist at ACOE Core Learning