The "Easy Eight" side of the tray appears perfectly straightforward, just a simple square. The problem is that it's kind of tricky to figure out how to get all five letters to lie flat at the same time: so many cute ways to fit the letters together, only one way to actually pack them into the tray. Bob couldn't just leave it at that, though. No, it wasn't enough for him to create a really clever and elegant puzzle. He had to do it twice, with the same set of pieces. The (unique) solution to the "Hard Eight" side of the tray is equally clever, and equally elegant, and awfully tricky to find! It probably never occurred to you before, but an ellipse doesn't have any corners. None at all. There's no obvious way to start on this side, no clear surety that you're making any progress at all until, suddenly, there it is: the pieces are really, really close to fitting in. A little more tweaking, some tiny adjustments, and then you realize you're still not putting them in correctly!