Once you’ve beat the game on Normal, “Flashback” to Case 3 – Henry. This case has an easy version of the Jigsaw Box mini game. If you don't beat the best time, just restore the checkpoint and try again.
WARNING: If you complete the box, you get a checkpoint. So therefore, you have to be pretty confident you beat the time. If you think you didn't beat the best time, DO NOT COMPLETE THE BOX. Just restore the checkpoint with the box incomplete and try again.
This is one of the few puzzles that you can walk up to but not select the game immediately. Instead, walk up so you can see it but DO NOT press . Pause the game and take a long look to get a plan together, then unpause and start it up.