EDIT - Here's the release trailer:
Here's a screenshot:
So what is Fold anyway? Fold is a puzzle game where you have blocks that collapse into each other in a chain reaction. The goal is to finish each level with just one block of each color. Right now there are 3 worlds, each world introduces a new concept.
Fold was written in Objective-C. The game is free to play, but you only have access to half the levels on each world. A single in-app purchase unlocks all the levels in the current version and all future updates.
Here's another screenshot: