54
in all fairness though they're very cute and there's nothing wrong with making the entire outside portion of your fortress a giant equine/goat/cat/bird sanctuary for your animal trainers to frolic in while you send miner after miner to their watery graves (after all three of the fortress' military squads were killed or maimed fighting two forgotten beasts that made their way out of the caverns into the hallway leading up to the fortress) in the cavern fifteen layers beneath all the unicorn vomit....we're rich in rope reed and barley
I'll have to check it out then... seeing it layer by layer it a little underwhelming. I'm assuming you can turn it off and on?
Yeah it's just a visualizer plugin for DFHack - here's one I took with like z-levels 12 through -40 or something showing.