Art Scrambles for iPad
...you can choose the puzzle piece shape by tapping Shapes in the bottom-left corner?
...you can restart a puzzle with a different shape and size by tapping and holding the Assistant control in the bottom-left corner of the puzzle.
...when the Assistant is active, tapping a puzzle piece pushes the tapped piece to its correct location. But tapping-and-holding a piece pulls the correct piece to the tapped location.