Today’s free iPhone app at FreeAppADay.com is Letstans Deluxe, from Grabarchuk Puzzles. Letstans Deluxe is the newest version of the tangram game, which is unique in the fact that it contains no in-game ads.
As of this writing, the game contains over 1200 individual tangram puzzles, spread throughout 10 different gameplay modes, and more puzzles will be added in the future, also for free. There are modes varying in difficulty from easiest to hardest, so everyone should have a chance to find something they like here.
There are 50 different colors of pieces in a few of the gameplay modes, and you can switch between more than 7 different skins when playing in Classic+ mode (the mode that sees you simply rearranging geometric pieces to fit into a blank outline).
There is a hint system if you get stuck, a timer that counts down as you play, and even a guest player option, so that your non-iPhone owning friends can play as well.