Hmmm...
Maybe there are enemies of certain shapes and you have to make the same shape and overlap them to defeat them?
The enemies would just like...disappear (screenshake, particle effects to accompany it obviously, maybe there's a points system?). I think the blocks around you would disappear too. If you collected too many it just wouldnt work, you have to be the exact same shape. So you kinda have to avoid these weird tetromino-like enemies while collecting squares in certain spots. I dunno how fun that would be tho, just an idea
Yeah, I kinda had tetris come to mind when I saw this, and I was thinking of some way that you had to fill a particularly sized spot with the right bricks attached to yourself.
But I was thinking of it more in a puzzle sesne, where you had to say.....fill a chasm with a bridge for someone else to cross.
This idea just seems to be a more pure version of that mechanically.