"A Cat gym for chubby paws and swinging bellies: Run, Kitty. Run! If your indoor cats are putting on a little extra weight, you could try getting them into this running wheel. It’s highly unlikely 15-pound Tigger will take to it but some of his slimmer siblings might. Every little bit counts."
77” Cat Gym Climbing with Cat Condos - Overall size 77"Hx36"Lx31" W - Board material Plywood - Covering material Faux Fleece - Base 26"x24" - Max holding weight 80lbs - 2 large cat condos, lower cat condo is 20"Lx14"Wx13"H with 28"Wx8"H entries, upper cat condo is 14"Lx14"Wx13"H with 2 8"Wx8"H entries - 3 large comfortable nests 14"x14"x2” - 10 sisal cat scratching posts. They measure 3.5" and are wrapped in 1/4" sisal rope.
Old tires can easily be found,cleaned,and painted. Those beds could easily be made out of pallets and put a little pillow or blanket in it smile emoticon pallets and tires can be found for free so it could be a cheap DIY project