This is a patchwork pattern called Storm At Sea. It's fairly complex if you do it with templates -- I did it the easier way and made this square using the foundation paper piecing method, where fabric patches are sewn onto a printed pattern. It's a lot easier than it sounds, and it can produce some exquisite results.

I chose the colors in this block because of the pattern name, although the full-size quilt I intend to make is going to be in our bedroom colors of hunter green and golden beige.