Why the DVD logo never hits all four corners

Why does the DVD logo never hit all four corners? Move it one pixel right and one pixel down every frame. In a box 1,600 pixels wide and 900 tall, the first corner comes at frame 14,400, the least common multiple of the two sizes: 240 seconds at 60 frames a second, if it starts lined up. Then both directions flip at once and the logo bounces between the same two corners forever. Idea and structure: Mark Rober's Short "The REAL Truth Behind the DVD Logo". #shorts #math #dvdlogo Idea and structure from Mark Rober's Short "The REAL Truth Behind the DVD Logo" https://www.youtube.com/shorts/vqjc5M0