It’s a kind of rappel dance troupe that I’ve seen perform before. They use auto-locking rappel devices called GriGri’s to lock the person to the single dynamic line and then they can do their flips and turns in the air without fear of the device slipping.
Cool, thanks for the info. I actually saw them again biking past the library yesterday. I reckon when I saw them on a building on Granville st. it was for practice. That was months ago and they were kinda tucked into an alley or something.