This is very interesting! In fact, I need to show this to Bruce's brother and SIL. He was just hospitalized last month and they discovered it is because he is highly allergic to their three cats. Mind you, he's been living with these three cats for YEARS! But his throat is all scarred up and it is affecting his airway. So now they have to build an enclosure to keep the cats outside. Bruce's other brother will like this because he is also allergic and can't stay at the house too long without having problems.
So their structure will be only outdoor. They will have to build shelter for them to use during the winter months. I'm curious as to what they will come up with. But this has great ideas!