Simply move the
cue ball and
object ball to the positions above and you now have a lovely intermediate/advanced practice skill. Even a professional pool player will drill in this manner.
Having trouble pocketing the ball? Try one of more of the following to get more comfortable:
1. Move the cue ball elsewhere in the box and try again (or closer to the 1-ball outside the box, as long as you are not shooting a straight-in shot). The goal is not to frustrate the beginner but to give them the chance to learn the interplay between the balls.
2. Move the object ball closer to the pocket. See above.
3. Change the object ball. Color-blind players and others have trouble with depth perception and certain colors of pool balls. I sometimes find it hard to see depth along the surface of the purple 4-ball, for example.
4. Left-handed players may want to flip the box and 1-ball to aim into the other corner “C” for freedom of movement.