Color-and-Weave Effect Calculator

Color-and-weave patterns like log cabin, houndstooth, and shepherd's check don't come from the weave structure itself — they emerge purely from alternating light and dark threads in a plain weave or twill. This calculator models that by treating warp and weft each as a repeating sequence of two colors: you set how many ends make up one warp color repeat and how many picks make up one weft repeat, plus what percentage of each is "color A" versus "color B." From your project's total ends and picks (width/length times sett), it works out how many complete repeat blocks tile across the whole piece, and the physical size of one repeat unit in inches (repeat ends divided by EPI, repeat picks divided by PPI) — the dimension you'd actually see as one visual motif on the cloth.

The more interesting piece is block-type probability: at every point where a warp thread crosses a weft thread, the intersection is either color-A-over-color-A, A-over-B, B-over-A, or B-over-B, and the calculator computes each of these four probabilities as simple products of your warp and weft color percentages — this is what actually produces the visual texture, since a heavily A-weighted warp crossing a balanced weft will read very differently than a 50/50 warp crossing a 50/50 weft even with an identical repeat size. Note that the yarn-per-color estimate is a simplified blend of end-count and pick-count percentages, not a true yardage calculation — it doesn't yet know your actual warp length or fabric width, so use it only as a rough ratio for planning proportions between colors, not for buying exact yarn quantities.