Tetris with half hexagon

Hi everyone,

I desperately need som help...

I have to realize a little Tetris like flash game, except that instead of square based shapes, I need to deal with half hexagons !

I did several tutorials and downloaded a lot of sources, so now I understand how to code a basic Tetris. But when it comes to use triangles instead of squares, it gets too hard for me !... How to detect when the shapes collide ? Can they rotate ?...

Well I'd be so grateful if someone could help me !!

PS : Sorry for my bad english...