I've been dreaming of building cat environments since I first read Bob Walker's book, The Cats' House years ago. I've been successful at getting various cat trees by the windows in my home, but yearned to build climbing things for my kitties. A few weeks ago I had a moment of inspiration and made a make-shift shelf for Diana who sits for hours and hours in the front lanai watching for lizards. I had two acrylic display cubes leftover from my gallery in Sausalito, and I bought the board and pole for $10 at Home Depot. I had the sisal in my garage. Voila! A kitty shelf.