A full-sized cartoon is drawn for every "light" (opening) of the window. A small church window might typically have two lights, with some simple tracery lights above. A large window might have four or five lights. The east or west window of a large cathedral might have seven lights in three tiers, with elaborate tracery. In medieval times the cartoon was drawn directly on the surface of a whitewashed table, which was then used as a pattern for cutting, painting and assembling the window. The cartoon is then divided into a patchwork, providing a template for each small glass piece. The exact position of the lead which holds the glass in place is also noted, as it is part of the calculated visual effect.