i am ambidextrous.
i write slightly faster with my right hand and slightly neater with my left.
here is a quick test to determine the ambidextrosity of people.
pretend you are pedaling a bicycle that is upside down in your garage with your hands on the foot pedals (while you are behind the bike).
both of your arms work in unison and travel in the same circular direction in that scenario.
but imagine one hand had to crank the pedals forward, and one had to crank the pedals in reverse at the same time.
ie 2 opposing circles.
only people with ambidextrous ability can do that easily.
trace the idea in the air with your hands, and you will see it is very hard for most people to do.