I used to see this guy riding around near my office in Boston. I have a great amount of respect for most folks who tinker and listen to a different drumbeat, but why the hell you'd want to produce this monstrosity is beyond me.
Drastically limit vision on one side (unless your head rotates like in The Exorcist) and make turning left a completely different physical experience than turning right?!
Every time I saw the guy I'd be amazed another day went by he wasn't creamed in traffic.
Or Darwin for that matter, LOL! Sorry couldn't resist. I built a home made swingbike, but never even had the thought or inclination to do this? Swingbikes are a blast. At full swing I can literally do a 360 in the length of the bike, while moving. What fun My neighbor walked up once as I was rolling it out. Him and his son just stood at the fence in disbelief lol!
It's a bike that turns both at the forks, and at the seat tube/rear wheel. You can do all sorts of weird stuff. They take about 15-30 minutes to get going, but once you figure it out, it's like riding a bike(pun intended, lol).
An example of a home made. They were also mass produced for a while until kids started cracking their skulls, etc.....