The Gold Award-winning object puzzler Shadowmatic is the Free App of the Week on the App Store.
This is actually the first time the game has been available for free. But this promotion won't last long so make sure you snatch it up as soon as you can.
Shadowmatic is all about finding the hidden shapes inside shadows. You rotate an object in front of a projected light until a familiar 2D silhouette appears. Harder levels give you two objects to play with.
Our reviewer said that Shadowmatic is "simple to the point of beauty, and beautiful to the point of becoming a work of art."
He also added that "this is a game you won't want to win, because you won't want the experience to end."
You can grab Shadowmatic on the App Store. It'd normally cost you £2.29 / $2.99.