Gorgeous. It goes without saying. As for the pattern, from looking at it I am going to venture a guess that it was made by braiding wire of two or more different types of steel, then bending it back and forth in a series of tight S curves and forging the whole thing together. You can see both the braided pattern, and the S turns near the eges. I know it sounds like it would be a very weak ingot, but I has seen some pretty damn amazing things done with pattern welding, notably by "Grandpa" Daryl Meier.
http://www.meiersteel.com/main.html