Perspective, with the Reason of Shadows and Mirrors

An engraving depicts two men in a room using a perspective drawing apparatus. On the left, a string is anchored to a wall at point H with a weight hanging from it. The string extends across the room, passing through a vertical wooden frame mounted on a large table. One man stands on the left side of the table, leaning forward to look through the frame, holding the string taut. The string passes through the frame and reaches a second man on the right. The second man stands behind a large cube (labeled with points A, B, E, F) resting on the table. He holds the end of the string against a specific point on the cube. Between the two men, attached to the vertical frame, is a hinged wooden panel, or door, that has been swung open. On this panel, a perspective drawing of the cube is being constructed, with points labeled C, D, G, and H corresponding to the vertices of the physical cube. In the background, a shelf filled with books is visible on the wall. The scene illustrates the mechanical method of capturing linear perspective by tracing the intersection of lines of sight, represented by the string, with a picture plane.