These are samples of cat rooms at Best Friends Animal Sanctuary in Kanab, UT.
The photo below illustrates how to deal with shelves and boxes in the corner of a room.
Note that the holes in the boxes face out toward the room. This was to make it easier for caregivers to see if a cat is in the box. Second generation boxes all have the hole on the topside of the box. This is to allow cats to reverse direction of travel. Notice the blue box in the photo below; once a cat enters the box, it cannot turn around but must back out of the box.
Notice how these shelves and boxes below stair step up the wall to reach the highest shelf on the upper right, where there is a cat door to the outside rafters of the cat run. The yellow box below, allows the cat to enter the box from below, then stretch up to the next shelf to exit the box
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