Put a box down, and a cat will jump in. Cats love cardboard boxes. It provides a feeling of safety and they are attracted to the material. I find that cats prefer the smaller boxes that are about 4 inches tall. They like it when they just fit. The bigger boxes are fun for games. Cut out a few holes, and it becomes a fun tunnel. We always have a handful of cardboard boxes around our main living area for the cats to enjoy.