The idea reminds me of that toy we used to make when we were little kids...you'd take a disc and put a couple small holes in the center, put a loop of string thru them and wind it up...and you'd pull the loop ends with the disc in the middle and it would spin one direction, then the other. Has to be something like that principle, only you'd resist it spinning once past the "center" point.
I can't imagine how that thing amused us for very long...
I do because I can.
I can because I do.
Squat, bench, chin, deadlift, dip, row. The rest is secondary.