Some other stuff people might be interested in.
Proving the sum of squares formula visually. Appeared in Mathematics Teachers Bulletin, 1993. Hebrew
Finding geometric proofs by cutting and pasting. Appeared in Mathematics Teachers Bulletin, 1998. Hebrew
I once had a plan to say a lot more about this topic. Since I moved to other things all that remains is the juvenilia above.
My long abandoned blog about the Hebrew language can be found here.