I agree with everyone who said "good question!".
What makes it very difficult is that they can "adopt" a piece of furniture even after years they ignored it
Kiri right now begins to lie under the sofa on her back and to drag her along with claws, a technique, Tigris had developed which successfully ruined our old sofa. But now it is a new one......
And Tigris and Kiri never met.
Orion has a new habit. He scratches the glass of a picture that hangs fairly deep when he wants to have somethng to eat. On the picture is a watercolor of a light grey kitty standing on its backpaws to try and catch a toy. Do you think he knows that?