EYE-HAND SPEED: "Z Ball"
This is a soft solid rubber ball with six protruding areas, so that it has an unpredictable bounce. It is useful in training eye-hand coordination when the subject has to catch the ball after it bounces, but it is not measurable.
"EYE-HAND SPEED is the time required to perceive and respond with the hand(s) to a visual stimulus. It is the ability for the eyes and hands to be not only highly coordinated but fast. The best boxers are often said to have 'fast hands', ie, they can throw a volley of punches in a second. Table-tennis players, too, have very fast hands. A deficit in this parameter makes for slower responses, poor timing, and the sportsperson may appear sluggish."
The Poor Man's Solution, get a soft solid rubber ball (about the size of a soft ball is good, depends on your preference), and glue bits of rubber for an unpredictable bounce.
If you hear a voice within you saying that I am not a painter, then by all means paint and that voice will be silenced.