In Sally's studio, an actual tree – a local sycamore downed in a storm – and a custom spiral staircase lead to a shelf under the top windows and then to a shelf passing into the adjoining sitting room. The cats have been seen using the staircase on occasion, but most often they just jump up to or down from an intermediate shelf. This photo was made just before we moved in.

A shelf made from a 2 x 6 crosses the sitting room from Sally's studio (on left) to Randy's study (on right). Cats can reach the shelf from the tree in the studio or the stairstep bookcase seen on the right.

The mailboxes can be closed on the rare occasion that we need to confine a cat to one room. This one leads to the top of a set of bookshelves in Randy's studio

A custom stair-step bookcase leads right up to the cat shelf. This is their most common way to go up and come down.

A custom punched-tin cat door into the laundry room where the water bowls and litter boxes are. They prefer this door even when the main door is open.

All cats love a big, tall cat tree. Cats live in a much more vertical world than we or dogs do.