In the video, a man with long hair and a beard is standing in front of a blackboard. He is holding a red marker and drawing a diagram. The diagram consists of a large circle with a smaller circle inside it, and a line connecting the two. The man is explaining the diagram as he draws it. The video is shot from a side angle, and the man is wearing a gray shirt. The blackboard is black, and the diagram is drawn in red and green. The man's voice is clear and he speaks slowly and deliberately.