In the video, a man is writing on a whiteboard with a red marker. He starts by writing the number 1000 in the top left corner of the board. Then, he draws a square around the number and writes the number 1000 on the top and bottom of the square. He then writes the number 500 on the left and right sides of the square. After that, he writes the number 500 on the top and bottom of the square. Finally, he writes the number 500 on the left and right sides of the square.