My daughter likes to collect souvenir baseballs whenever we go to ballgames. Her collection is starting to get pretty big though, so I wanted a way to be able to display them in a space efficient way. I realized that with a little design work I could make something that would let me stack the balls on top of each other in a very stable way that also looks pretty cool. You need one of these between each layer of balls that you want to have. The result is very stable. In fact you can pick the whole thing up and move it around pretty easily (at least with the 5 layers that I have).