A short article by Ralph Griswold on determining whether two weave or fabric patterns are the same apart from row and column rotations (circular shifts). It describes a procedure for reducing a binary pattern to a canonical form that is identical for all rotated versions. A worked example compares two patterns, one taken from Oelsner's Handbook of Weaves, using a 24 by 20 binary array. An appendix gives the procedure in the Icon programming language.