Hello, I'm working on a match-3 game where blocks "fall in" from the top of the board, rather than just "appear" in the top-most space. What I'd like to do is dynamically create a BitmapData mask that is in the shape of the 8x8 board and attach it to the group. This way any blocks that drop in outside the boundary of the board can't be seen until they slide in. It seems like the only way to do this would be to create a mask for every sprite that is dropping in, and dynamically adjust it every refresh. Either that or maybe crop new blocks as they are dropping in. Is there a better way to do it?