A simple design for stacking bins/shelves that can be used to hold things on. There are 2 different models for ones that stack and one for the top which does not include the stacking part. They have small holes to be able to stay sturdy and not slide or fall. They are not big enough to hold 8.5 x 11 inch paper, but they can be used to hold other things including markers, small boxes, and other things.