proportion.
The width provides continuous gray for yardage of narrow fabrics and repeated flag (right side) for wider fabrics. At a distance, you may see a tread pattern; this is variation in pebble values, and will not look like tread when zoomed in. At this time, denim is 56" and includes two checkered flag borders. Twill shows both and beyond at 58". Poplin and Kona show grey to the right. A swatch could make a chess board. Print always starts at bottom left corner.