1. Click on the piece that you want to move.
    (the piece will then be highlighted in Red).

2. Click on the piece where you want it to go.

3. Click Reveal - The puzzle will be covered in blue diagonal lines.
    The blue diagonal lines cover any piece that is in the wrong
    position. Clicking "Hide" will remove the blue diagonal grid.

4. Use the "Mix" option to re-mix the puzzle pieces.
    Be careful though, this will move ALL of the pieces,
    not just the ones that are not in the right position!