sentence: A man talks to the camera and demonstrates how to climb a rock wall using another person as the exhibitor. sentence:   A man in a green t-shirt talks to the camera while standing next to a rock climbing wall interspersed with still shots of the wall and the wall elements (ropes, labels). sentence:   A man is shown climbing the wall while strapped into a protective harness. sentence:   The man returns to the wall and shows taped markers on the walls with numbers on them.