Example where I didn't touch lumbar or chest and everything was equal (i.e. both pecs extended or contracted at the same time):



doesn't make sense to me

why though? i imagine it wouldn't be too hard to make stuff symmetrical

One thing I've noticed is that if tori and uke don't interact in any way, red side (tori) tends to be completely symmetrical while blue side has minor imbalances that eventually cause obvious asymmetry.