Painting with Watercolors, Glue and Salt. This will be a fun project this summer, just paint the canvas with watercolors. add some kosher sea salt (coarse is better than fine salt) and some glue splotches!
My husband built one of these for our feral cat "Ghost Cat". He, and the other strays, have used it every winter and on rainy days. It is easy to make and they seem to like it. Outdoor cat house shelter for outdoor cats