An appendix to my A-Z article on Spi-n-t, this page from his epic comic 'Yosauro' shows a device more like the gym horse which started this series than the sharp wedge alternative we have seen lately. There's a nice lock-in moment in the first frame.
This variant has insect-like or perhaps reptillian form (from Yo-sauro?). Also the capability to grow a rather substantial horn mid-ride to entertain the trapped rider. Unfortunately the supervisors are distracted by the arrival of royalty just as the fun starts.
To see other artists interpretations, click on the 'Riding the wedge' label below