We love using Osmo in our office. It is proving to be everything I hoped it would be when we first ordered it. Here is a brief explanation for how Osmo works. You can also watch this cute YouTube video showing Osmo in action:
Osmo has just released Masterpiece, a very clever new free download for the iPad that will add a new dimension to eye-hand for drawing readiness.
This reminds me in a way of Marr’s primal sketch model.
In essence, Osmo deconstructs a real object or image into its primal sketch, and allows the child to reconstruct or sketch it back to the original. How fun!
The VisionHelp Blog 
I like the pencil grip. Gary
What a great way to have fun with Tangrams !