Using wide rubber bands wrapped around the last links, this robot
grips and twiddles a ball between its fingers. Each finger has three joints,
which can bend forward and backward.
Using balanced motions, the fingers can even roll the ball back and
forth while holding it steady in space, similar to the way a human can roll a
marble between thumb and forefinger.
At lower right, the ball is gripped from above, helped by the fingers'