Motley Blocks is a just-released game from Square Enix, now available on the App Store for $2.99. I first saw this game back at E3 this year, so it's been in development for a while. The polish and performance of the game definitely shows that development time, even if the basic premise of the game is fairly simple.
The idea is that you start out with a sculpture built of little voxel blocks, and at the beginning of each level, that sculpture is exploded into a sort of cylindrical lap of the colored cubes. Then, as the circle turns in front of you, you can line-draw your way through similiarly colored blocks, re-placing them in the sculpture, and forming a new 3D picture.
It's fun, and honestly a little too frantic, as you can see below -- you need to match all of the blocks to complete a level, and that can actually be pretty tough, even when the game is just starting out. But it's all relatively forgiving, and even as things get complicated, a few tries will usually get you where you need to go.
Motley Blocks has over 80 puzzles (as well as the ability to create and play custom games if you register a free account), and for all that content, the full price of $2.99 isn't that much to ask. If you don't want to jump in on that price right away, there's a lite version to try as well.