Construct cat condos to hang on the wall! Cut a piece of wood for the back of the condo and cut a large piece of PVC pipe to the same length as the wood board. Cut a hole in the side of the PVC pipe or cut off an entire side of the pipe and drill the pipe onto the wood board. Glue pieces of carpeting onto the condo, hang the condo on the wall and make additional condos, stairs or carpet-covered shelves for your cat to access the wall bed.
Source: Morena Pet Hospital