I shouldn't be awake right now, having a midnight snack and checking in, so forgiveness if this is incomplete or illogical.
Does yours use a planetary gearset? Maybe the motor rotates the "sun" gear" to turn the "planets", and the merry-go-treadmill is connected to the outer race (forgot what it is called) and you walk to counter the motor. Essentially, whoever is going faster wins, but if the motor goes faster, you get pulled inward. This would also make your effort go further, as the closer you stand to the middle, the more you will accelerate the outer race. For a neat trick, the operator could reverse the direction of the motor without telling the victim, and they would experience pain before realizing they must reverse direction.
(this idea intrigues me so much, I won't even point out the irony that we are using 1000 words to paint a picture, when the point of this thread was to post the picture, and have the 1000 words be posted to explain. Not doing that, not mentioning that, just letting everyone know how much it intrigues me to make me ignore that. ) (Seriously, not saying anything, not even thinking it.)
Bondage is like a foreign film without subtitles. Only through sharing and practice can we hope to understand.
A Jedi uses bondage for knowledge and defense, never for attack.
I am so smart! I am so smart! S-M-R-T!....I, I mean S-M-A-R-T!