CONGRATULATIONS!
You have found the fifth of my secret pages! What you see above is Eiichiro Oda's original design for Don Krieg's Jolly Roger as it appeared in One Piece: The 2nd Log. As you can see, the skull began as a single hourglass which eventually became two on either side. In looking at the bottom design, without the supporting bones on the side it is quite close to the final design.