A great tool that I have began to play around with are Proof Blocks. http://www.proofblocks.com/
They are easy to use and a great tool for advanced geometry where students are confused with angle congruencies and triangle congruencies and just getting started on proof writing. BOOM!! Proof Blocks, simple to use for almost any proof.
- Naturally prevents flawed logical arguments
- Facilitates working forwards, backwards or from the middle of proofs
- Allows students to easily verify the correctness of their work
- Supports visual, kinesthetic and English language learners
It is an easy way for students to gather and organize information and their thinking. Here is a link for the complete list of the proof blocks and the accessories that come with them. Happy Teaching!