The technique is called "Stack & Switch" Basically, you make a light colored board & a dark colored board, stack them, then cut your curves on the Bandsaw. Then you can switch the pieces to get the multi-colored effect.
So Razor, then you must be sticking on a pattern on both boards and cutting them in a band saw? My problem would be to cut them both so accurate that they fit with the tight joints that I see you have. That is the part I don't get or maybe I just haven't mastered yet.
Yes, Danoaz; The challenge is that your blade needs to stay perfectly vertical as it cuts through both boards. I use Carter ball bearing guides on my saw which helps a lot but it does take some practice. On a board like this I would do my horizontal cuts, glue up, restack, and then the vertical cuts, and then a second glue up.