Toile:

Fashion’s error-scapes, the toiles are prototypes whose inexpensive fabric allows for low-stakes failure. Usually they are made of unbleached muslin, though any simple material on hand will do: recycled bedsheets, deadstock (surplus textiles from a production run that would otherwise be discarded), or another deconstructed garment. Toiles are sometimes called muslins, after the fabric of which these garment dry-runs are typically constructed. The toile is a practice staple–to fashion what the barre is in ballet. It is made after the first run of a pattern is cut, and might be used to rework the pattern if its fit isn’t right. A toile is often marked up in ink, stitched and restitched, with edges left raw and unfinished to facilitate multiple adjustments. Treat it like a page in a notebook that is waiting for your marks, or an instrumental etude to be gone over and over again.