I inherited a Peugeot folding bike recently, and although it's a little beat up, it's mechanically sound. There's a large hinge in the center of the downtube and this folding/locking mechanism seems to work great.
It's got a coaster brake, and that's when I noticed something cool. It's got a kickback hub.
Each time I backpedal, an internal gear shift occurs and changes the torque. So when I'm going up a hill, I may be in the low gear, but when I reach the top, I pedal back a quarter-turn, which shifts gears, and then resume pedaling forward in high gear. Genius!
So is anyone familiar with these? I'm not really concerned with keeping the bike, and wouldn't mind selling it.