So did some research, and stole a piece of four different coloured papers and a white and brought them home tonight.
Here's the old one and all the paper cut up. The ones on the right were the offcuts.

One tetrahedron..

Two tetrahedrons..
Three tetrahedrons..
Four tetrahedrons..
And finally, five intersecting tetrahedrons!

Three tetrahedrons..

Four tetrahedrons..

And finally, five intersecting tetrahedrons!

Fiona
That's awesome :)
Kazza the Blank One
Thanks :)
Kazza the Blank One
oh yeah, waiting for someone to tell me it's tetrahedra not tetrahedrons.....