Rauschenberg created the pyramid or triangle form of each Pyramid Series work by pressing a folded piece of fabric between two heavy sheets of paper in a flatbed press. The pressure created by the press produced a raised triangle on the paper—the ghostly impression of the cloth within. In this detail view of the verso of drawing 1C (SFMOMA 98.300.3), a slightly raised line left by the press runs just above the inscriptions.