The shelf design, which is shown in blue tape along the second row of pictures is based on the idea of Shephard's Spiral/Tone (barbershop pole), the idea is that the cats, while in a confined space, can run in infinite circles up or down.

The gray catio in the background, which is now built and attached to the main catio is something I bought online. It seemed way too flimsy to protect the cats against wild coyotes, and within a couple of rainy seasons, the mesh on it is rusted and brittle. We give the cats access to it when we are outside so that can still experience dirt, etc.

We are using CatScapes hinge-brackets to make the diagonal shelves with ease. We'll probably finish this catio in the summer/fall of 2024.