Sly 3: Honor Among Thieves Tips

References? Maybe...
Go to Dead Men Tell No Tales for these strange... occurances. They may have been references on the producers part or it could be coincidence.
You Decide.
Go to the front door of skull keep, where there are two curvy patterns on either side of the door. Unless I'm mistaken, the left one looks like the "S" out of Sly on the cover. Also, at the top of Skull Keep, go to the door furthest away from the stairs. To the left are some broken battlements that look alarmingly like hearts with cracks down the middle.