If they've gotten this far, they've already been iterating. In fact he says so at the beginning. "A year ago I welded two bicycles together..."

Having built two recumbent vehicles (a bike and a trike) I can say that the options for a rear wheel drive are either:

- Single wheel drive

- Dual wheel drive with freewheeling action

   - The inside wheel is driven in turns

- A differential

   - The outside wheel is driven in turns

- No differential at all

   - Both wheels are driven equally all the time

He's chosen the latter. It's simple, cheap, and provides the best traction in almost every situation except a turn. It's a good compromise for where this thing is intended: Dirt. If it were optimized for street use, he'd just drive one wheel, which is what I'm doing with my own trike.

For reference, this is my current trike build. It's not done yet. Needs finishing, and paint:

https://i.imgur.com/pnrDQMS.jpg https://miscdotgeek.com/wp-content/uploads/2019/11/IMG_20191...