THE "OFFICIAL" 9-PIECE PUZZLE: HINT #1 

If you look at the nine pieces carefully, you’ll notice that there are six cards featuring Dick Difficult’s head, but only three cards featuring his legs. Also, there are five cards showing Don Difficult’s legs, but only two pieces featuring his head. This means several of Dick’s heads and Don’s legs must be on the outside of the puzzle… not requiring an adjacent connecting leg or head.