I was answering about the Northern/Southern hemisphere logic of this... and realised that it depends if the sundial is vertical in a wall (facing South in the Northern hemisphere) or horizontal (facing the zenith/sky)... today you can easily find those wall sundials in many monumental buildings (at least these seem to me more common than the others) and the shadow is casted counterclockwise in the Northern hemisphere, so not sure if the clockwise sense was locked by sundials... also in the Southern hemisphere logic flips completely.