Here is a picture of Maddi's desk-tidy. She decorated it with straws, and had a lid on a hinge. There were lots of others that worked out well too.
Some people had to make lots of modifications to their original plans. Ethan had one that had room to put PPA's as well, but he still had some work to do on the base of it. And Shae designed one with cotton-wool padding round the top so it was warm and quiet. Some people designed them to fit on the inside of their desk-lids.