What a throwback. I remember reading this guy's build of the "Flying Nimbus" [1]--an early version of the Onewheel--back in 2015. In fact, the Flying Nimbus and the Onewheel were both released in 2014, but it appears they were produced independently, once again demonstrating the curious phenomenon of Multiple Discovery [2].
[1] https://transistor-man.com/flying_nimbus.html
[2] https://en.wikipedia.org/wiki/Multiple_discovery