It’s just a regular braid, but instead of taking 3 equal sized pieces like you do in a normal braid, you just make one piece smaller than the other. U can see how one section is smaller in the braid if you look @ the top photo.
This is a great idea for any sort of DIY artwork: trace a simple graphic onto three canvases, and paint. So much more esthetically pleasing than if you were to just trace and paint onto one canvas. Plus i love the whale idea for a little boy room :)