I expand my mind-control experiments by creating diverse exercises to force my brain to separate the movement of one hand from the other, so they can work independently of each other.
For example, I would draw an imaginary four pointed square in the air with my left index finger while simultaneously drawing an Isosceles triangle with my right index finger, with both fingers moving at the same time. Another is to point my index fingers at each other and move the left hand in a circle toward my body while the right hand simultaneously makes a circle away from the body, then I reverse the directions of the circles, or simultaneously trace a circle and a square with the other, or trace a five-pointed star and a three pointed triangle.
Next, I apply these brain tricks to what I love most: cards. I learn to shuffle a deck in each hand; do a one-hand shuffle while performing triple cuts with the other; fan half-decks with both hands; and do simultaneous one-hand shifts with both hands. This is the most ridiculous example of close-up juggling of all: Roll five silver dollars across the knuckles of one hand while performing a longitudinal one-handed shuffle with the other.