A pattern is spinning. I saw the pattern rotate clockwise for the first time. Somehow, it turned counterclockwise. Why do I see the pattern rotating in two directions?

Consider a video camera, which takes pictures every 1 second. The object of taking pictures is 1 rotating the pointer, which rotates 359 degrees clockwise every 1 second. Now let's look at the records on the magnetic tape, and get the information that the pointer on the first film is 0 degrees, the pointer on the second film rotates counterclockwise 1 degree, and the pointer on the second film rotates counterclockwise by 2 degrees. If the motion of the pointer is judged only by the film, we will say that the pointer rotates counterclockwise at the speed of 1 sec 1 degree. But if the pointer turns 36 1 degree clockwise every 1 second, we will think that the pointer turns clockwise and the speed is 1 second1degree.

Because of the visual persistence effect, your eyes are the camera, but you can think that your eyes take pictures every 0. 1 sec/time (the image will stay in your mind for 0. 1 sec).