In all honesty, it looks pretty darned straightforward to me. Most likely based on a layer cake (10" squares) - - use some as 10" squares, cut some in half 5" x 10" and cut some in fourths 5" x 5". In the Patio pattern, it looks like the designer cut some 2 1/2" squares as well. You can make the sashing any size you like. The 'Frosted Christmas' sashing looks a tad more narrow but it's entirely up to you.
I agree with the other post - get some graph paper and draft it out.