It's a neat concept - a nice, polished AR kit. The actual tangram concept is a bit disappointing though - dragging simple objects around on a flat surface is already something the iPad excels at. In this case it feels like it's somewhat obsoleted by modern touch-screens.

Obviously there are cases where touch-screens fail, but simple tangram puzzles work just fine with them.

I'd be interested in seeing this expanded to things that require too large a play-area to do conveniently with a tablet, or that involve manipulation that doesn't correspond to simple dragging (which you can already do well on the iPad).

Either that or focus on vision-impaired students. Maybe a set of braille algebra-tiles[1]?

[1]http://en.wikipedia.org/wiki/Algebra_tile