Don't have my books nearby, but it's an interesting grid.
It's 6x6, but (easily) constructed as 1.5, 1, 1, 1, 1.5.
Can't say I'm crazy about those salmon colors, but I do like the monochromatic coloring.
Sorry if this is a dumb question but do you mean this is only a 6" block when completed (or are those ratios)?