They’re a German invention and well known here. There are several variations, they’re usually a kind of sport/balance toy for kids and teens - but there are also some for medical uses. You can find some variants in pictures here: https://de.m.wikipedia.org/wiki/Pedalo_(Spielgerät)

They’re also a recurring German meme, although I don’t really know why. The Wikipedia link above mentions them, but only says that it started with an image of a guy on Pedalos with the caption “Bruder muss los” (Bro needs to go) referencing a situation that you want to get out of, but have only inconvenient methods to leave.