OK, it's really Christmas Eve today. Two different emails with videos on the same day. It does not happen often!
We enjoy your site so much, and it was an inspiration for us as we embarked on our cat ladder construction journey.
We actually got our cat, Mittens, when we were living in the Dominican Republic. There, she was an indoor/outdoor cat who would come and go as she pleased, letting herself in and out through slats in a window that we never closed. After, we moved to Haiti, where she lived with us in Port-au-Prince for a year. Same story there: Mittens would let herself in and out of the house whenever she wanted, as we just had open windows with bars on them.
Upon moving to Boston a few months ago, we had to figure out a way for Mittens to maintain her free-wheeling lifestyle while living in a second-floor apartment. It took a couple of tries and modifications, but here's our finished product and its happy user.
//Stephanie & David