The manipulation of perspective may be divided roughly into three main categories: the creation of artificial depth through overt foreshortening, thereby simulating the effects of distance on our visual sense; the use of psychological tricks that play on our instinctive presumptions regarding the existence of things unseen; and the masterly obliteration of all evidence of artifice, thereby rendering the deception invisible. Zen gardeners' discovery of the use of foreshortening in a garden took place at almost the same time that the Florentine artist Uccello (1397- 1475) began experimenting with natural perspective in his landscape oils. Although this example of artistic convergence can hardly be more than coincidence, certain of the devices were similar. As the American garden architect David Engel has observed, the Japanese learned that the apparent depth of a scene could be enhanced by making the objects in the distance smaller, less detailed, and darker than those in the foreground.1 (In the garden of Yoshimitsu's Golden Pavilion, for example, the rocks on the spectator side of the garden lake are large and detailed, whereas those on the far side are smaller and smoother.) As time went by, the Japanese also learned to use trees with large, light-colored leaves at the front of a garden and dark, small-leafed foliage farther back. To simulate further the effects of distance, they made paths meandering toward the rear of a garden grow narrower, with smaller and smaller stones. The pathways in a Japanese garden curve constantly, disrupting the viewer's line of sight, until they are finally lost among trees and foliage set at carefully alternated levels; streams and waterfalls deceptively vanish and reappear around and behind rocks and plantings. Zen artists also found that garden walls would disappear completely if they were made of dark natural materials or camouflaged by a bamboo thicket, a thin grove of saplings, or a grassy hillock.