"Exit" returns you to the main screen of the game.
"Lock" blocks the dragging and zooming of the game board. This option is useful if you want to concentrate on a particular part of a puzzle.
"Theme" allows you to select 1 of 9 background colors.
"Clear" removes all single puzzle pieces from the board.
"Hint" automatically combines random puzzle pieces.
"Preview" shows the full picture of the puzzle.