down perspective lines on your grid curve out like the lines on a football (Figure 2). Termes calls this the first curved-line perspective; it is a perspective that can give you vertigo!
    There's a different way to think about 4-point perspective. In Termes's "continuous" 4-point perspective, the zenith-nadir (up-down) lines stay parallel, but the east, north, west and south directions all become vanishing points. Imagine trying to reproduce a room around you by sitting with a drawing pad in a swivel chair in the middle of the room. As you face a picture on the north wall, it appears to bulge out, just as the east-west lines leading to the corners of the room in your peripheral vision converge. But as you swivel around in your chair and face an adjacent wall, it's now the north-south directions with the vanishing point for this wall is smack in the middle of the previous wall. Obviously, the drawing must suppress some of this intrusion of vanishing points. In fact, the way to approach continuous 4-point perspective is to start with a    long   strip   of   paper    on    which    north,    east,   south,

zons. With cubes, things just fit. And the cube happens to provide a wonderful playground for the study of perspective.
    Consider the worldly cube. It has three sets of parallel lines. If the lines of those sets meet at a vanishing point ahead of you, as a pair of railroad tracks might, you get one-point perspective. Artists got to this stage in the Renaissance. Two-point perspective takes two different sets of parallel lines on the cube to two vanishing points, say to the east and north of you (90 degrees apart). In 3-point perspective, each of the three sets of parallel lines on the cube has a vanishing point. If, on a page, we draw converging parallel lines from all three directions of the cube, we obtain a grid containing three vanishing points, which perhaps represent the zenith (above you) at the top of the page, and the north and the east at the lower corners of the page. (See Figure 1.)
    What in the world can 4-point perspective mean? Termes suggests two ways to grip this concept. For example, you can have vanishing points at the east, west, zenith and nadir (below you) - as if you were hanging onto middle floor of a skyscraper and peering above your head and below your feet. (If you do grip this perspective, you will be gripping hard!) In this perspective, something strange happens when you attempt to reproduce what you see onto a flat piece of paper. The zenith and nadir vanishing lines bulge in the middle of the paper (as you register nearby objects, such as the flagpole you are clutching) and they taper at the bottom (as you scan down the building or upwards to the rescuing helicopter) Thus the up-

west, north vanishing points are lined up along the equator of the paper. Elliptical grid lines for east-west vanishing points intersect with the elliptical north-south vanishing lines. When the page with its drawing is rolled into a cylinder, the walls and