So many suggestions
I'd do the following. I don't see the seams in the photo, but if it's not this then I don't know how they did it without Y-seams. Note that I've assumed 9" blocks. Sew the 4 vertical strips, then attach into a block.
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I guess you could make the red a 3.5" square - sew the small strips above and below it, then make the vertical strip with red in the middle, to avoid seaming your red square.