Created by designer Leslie Buker. "Cube" is a modular system, made from sheets of cardboard that can be fixed together with built in tabs and slots to create cube-shaped blocks. When these blocks are put together, they can make tunnels and towers and any shaped structure that cats can crawl through, jump on, shred and chew. It's a 100% recyclable alternative to the wood and carpet "cat condos" that many cat owners have. Owners construct their own, so it can be designed to fit into any space.