A system is provided for properly resizing a window shade to fit within a window frame adjacent a window. At least one ruler strip is provided with visible graduations thereon. Indicia are provided adjacent at least some of the graduations. The indicia are descriptive of a width of a window frame in...http://www.google.es/patents/US7194811?utm_source=gb-gplus-sharePatente US7194811 - Cutting guide for a window shade
