Try a new twist on crossword puzzles, in which clues and words are replaced by random lists of letters. Deprived of clues of where words appear in the puzzle, you are forced to use pure logic to determine how the random letter strings fit into the puzzle.

If you get stuck, feel free to take a hint - a small time penalty will be charged, and a cell will be filled in. Completed strings will be crossed off the list automatically. Complete the puzzle in the fastest time possible, then challenge friends - nearby or via Twitter - to beat your best.

The default puzzle size is 12x12 on iPhone and iPod or 19x19 on iPad, but additional puzzle sizes (smaller and larger) are available for purchase for 99 cents each or $3.99 for all five sizes (save 20%!).