This is a different way to make a two color Chevron (aka Zig Zag) quilt using 10 inch squares. which make up really great for a bed size quilt.
https://www.youtube.com/watch?v=hipG9u4TzMY
There would be so may seams in a placemat with a smaller zig zag that I wouldn't recommend using this for a placemat, but it is something for others to keep in mind.