Can you solve this?

I love the Veritasium videos by Derek Muller, a Canadian-Australian. He covers many topics in Science and other topics which are also of interest to the lay viewer. They are at a perfect level for students too. This video beautifully illustrates how science helps us to look for patterns. It would be excellent for use in ToK classes, or any subject in the sciences or humanities where we use the inductive method. Why not subscribe to this channel?

But first, can you solve the puzzle before he gives the answer?