sentence: A man is tied to the top of a rock wall and he quickly repels and the words "clean big falls!" appear on the screen. sentence:  Men tied up with safety gear are hanging from large rock walls and repelling very quickly either alone with other people on the same rock. sentence:  There are two men connected to the large rock wall, one is higher up on the rock and the other one is on the ground and when the man that is higher repels very quickly, the man on the ground quickly gets lifted from the ground but not all the way up the rock wall.