help with circus bike

I’m trying to figure out how to make one of those bikes that has the seat that rotates just like the handle bars, allowing the bike to be riden sideways. I think its essentially two unicyles welded together, but i’m not sure. does any one know where to find videos, instructions or stuff online about this bike?

Check out bike #3 on the list

oooooo… here you go

I think he meant this: A uni welded to another:D