The various puzzle apps (e.g. Anatomy Puzzles, Art Puzzles, Window Puzzles etc) all use the mechanic of dragging a puzzle piece with your finger to the correct place in the puzzle. By default the apps assume you are right handed and offset the piece to your left so your finger and hand do not obscure the piece while you are moving it. But what if you are left-handed?
Not to worry, all the puzzle apps have a left or right handed setting. To change from right to left (or similarly back to right), tap the corresponding 'L' or 'R' button at the bottom right of the puzzle choice scene. The setting will be remembered.
Setting to Left handed mode will now offset the puzzle pieces to the right of your finger...just what is needed to not obscure the piece.
Here is an image showing these buttons in Window Puzzles.