This video of hinged bikes is very goodbad
I found this bike video while searching for information about hinged "swing bikes" generally. They are a lively, if niche, bicycle-subgenre; the most typical one I see people talking about on reddit or other forums is the Swing King Bike, which uses a second tube attached to the seat tube to create a folding swing/hinge point in the center of the bike, below the rider's center of mass. This means that the frame can kind of fold in half while you ride it. To me, this sounds completely terrifying.
To the people in this German advertisement for the SNAIX NEUROBIKE (incredible name), having a bike that folds in half while your ride it is I guess good and healthy instead of bad. Every bit of this video is incredible.
I will never purchase or ride a bike like this, but good on you, weird acrobat boys, for finding the bike of your dreams. (This bike is discontinued and Did Not Catch On.)