Reference position: 40 − 20 = 20Aim: 20Start: 404th cushion: 20From the bottom-right corner (40) to the middle diamond of the top cushion (20). 4th cushion 20: the top-right corner.
991 System (991 시스템) · Drill cards
4th cushion = Start − Aim
30 − 10 = 20Aim: 10Start: 304th cushion: 20Start 30 (3rd diamond from the left on the bottom cushion), aim 10. 4th cushion again 20, the top-right corner.
20 − 0 = 20Aim: 0Start: 204th cushion: 20Start at the middle diamond (20), aim at the top-left corner (0). The ball comes back out of the corner and arrives at the top-right corner (20) on the 4th cushion.
30 − 15 = 15Aim: 15Start: 304th cushion: 15Start 30, aim 1½ diamonds (15). 4th cushion 15: 3rd diamond from the left on the top cushion.
30 − 0 = 30Aim: 0Start: 304th cushion: 30Start 30, aim at the top-left corner. 4th cushion 30: middle diamond on the right long cushion.
40 − 10 = 30Aim: 10Start: 404th cushion: 30Start 40 (corner), aim 10. 4th cushion 30: middle diamond on the right cushion.
To the 5th cushion: 40 − 15 = 25Aim: 15Start: 404th cushion: 25Start 40, aim 15. 4th cushion 25 (2nd diamond from the top on the right cushion); from there the ball goes, as the 5th cushion, to the 1st diamond from the right on the top cushion.