... 1.exercise' time is short,it is easy to learn,severial days can grasp 2.Good quality and ... at your fingertips. Suddenly, it multiplies to two. and, in rapid succession, to three and then four! One ball ... as magically as they appeared, the balls are caused to vanish one at a time until nothing is left ... :1.exercise' time is short,it is easy to learn,severial days can grasp2.Good quality and favorable price ...