In the 3rd puzzle you can't get backed in to a corner. If the pieces are in the right spot they light up. If the pieces are not lit up that means they can be moved. Once lit up, they are locked and all other pieces are free to move over them. There is no way not to get this game. You can rotate the pieces and place them whereever you want, but if they do not light up and lock then they are needed somewhere else.
I loved this puzzle the best. Once you get the first one, there are more to go with different pieces.