I received a mail:

Hi, I built this ladder for my cat, however…… he refuses to use it (so far). Seeing your pictures I’m still hopeful and I think there are no significant technical flaws. But if you have some suggestions on how to get the cat actually to use it, I’d be interested. He was an outdoor cat for the past 3 years, but now we moved here to Washington DC, and it appears he’s afraid of heights or something.

Photo: Thomas, Washington DC, USA.