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?

There’s a huge book of diffrent bikes you can build that was posted on the forums a while back.

Maybe somebody can find it… I think it included a design for a bike that’s esentially what you described.