Deceptively simple. Gingham is a neat pattern formed by intentionally offset stitching. At least, that's what I see when I stare intensely at my work shirts. If I made opacity changes and gradients available to me, this would have been a lot easier. However, I opted to create and manage a bunch of rectangles which were rotated, scaled down, colored, and clip-masked.
I will definitely be re-doing this one. There are flaws involving grouping, stroke color, and balance. Once again: theory is correct, but the execution got wonky. Trends being what they are, you can look forward to stickers featuring tartan, paisley, and argyle.