Welcome to cat-silly-rock, the catsle upon our deck.
Our feline fortress provides two floors, each with minimum 1.5 foot clearance. There's a large heated pad for the cats to sleep on in the second floor area, as well as a blown-air ceramic heater. There are also lights in each tower (1 watt LEDs), a hi-def security camera, built-in cat toys, and two entrances / exits to give them a means to bail if someone gets aggressive.
And yes, the drawbridge works. I got the snow off there so they can get in and out across the drawbridge... I just wanted to shoot it as it looked this morning. BTW, the main entrance was agreeably free of snow; you just can't see it in this shot, as it is inside the barbican.
It gets really cold here in Montana, so we wanted to build a cat shelter. We went a little nuts. :)
Other images of the catsle may be viewed in this Steemit post.