But what on earth is this?
Looks like it changes the circular motion of pedaling to a back and forth movement.
As to why? I'm not sure. Maybe useful to people with limited leg mobility(?).
That Bernds folder seem like a good alternative to Brompton! Did you have a go?
I didn't try one, nor did I spend much time looking at them for that matter. Folded size looks like its larger than the brompton tho'. Me, I'm after a birdy.