Slick Picks is the next generation of sliding tile puzzles. Think (generic 3d puzzle with colors on the side) on a plane instead of in 3d. You dont slide a single tile into an open space. Instead you slide an entire row or column which wraps around to the other side - move one tile into place, move three out of place.
3x3 and 4x4 puzzles are available free, along with 14 different pictures. A $.99 in game purchase unlocks the 5x5, 6x6, and 7x7 puzzles.
You may want to start with the number grid as you learn to solve the puzzle. Then move to the other pictures for a tougher challenge.
A note to the mathematically inclined and those who get frustrated putting the last piece in place: It is possible to flip the 15 and 16 pieces.
Special thanks to:
Mugunth Kumar ( mugunthkumar.com ) for help with the in-game purchase functionality.
Shannon Appelcline ( http://iphoneinaction.manning.com ) for help with the loading screen.
Photographs are from http://www.public-domain-photos.com