I have seen this at the Big E (New England state fair) It was in the midway games section. You paid 1$ for a chace to win $100. All you had to do was ride the bike 25 feet around a barrel and back to the start. I tried.....
It would be easy to build if your handy with machine tools and a welder. If you really want one let me know it sounds like a fun project.....
Tiller effect has to do with the swing of the handle bar on a LWB recumbent. It has nothing to do with what Info123 is asking about.
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Bentbaggerlen
"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." - Arthur Conan Doyle