Parabolically Shape at www.japanese-home-gardens.com

A parabolic antenna generally is composed of a parabolically shaped reflecting dish into which energy is radiated from a point source, such as a horn on the end of a wave guide. The dish may be cut away or its shape may be distorted to give the required shape to the beam of radiated energy. The antenna usually is mechanically rotatable and is driven by a servo system, which is remotely controlled from the indicator location. The control may be a hand crank or a slewing selector.

THIS INFLUENCES design considerably. Few plots are symmetrical, but that really does not matter. An L-shape or a triangle can even offer more design potential than a rectangle. Perhaps the most difficult shape of all is a square, particularly when it is too small to subdivide as in many yards in front. A design for an awkward shape needs to be carefully thought out. A long thin area, for example, can be divided into contrasting sections with barriers across its width, but by leaving a narrow view running through from one end to the other you create an additional sight line. Furthermore, by placing an ornamental feature like a statue or seat at the far end, you gain the full benefit from the site's length while the screens minimize the disadvantages of its shape.

The shape of the geoid is defined by its departure from a "reference ellipsoid" which fits most closely to the shape of the earth; in this case, the average level of the land and sea is taken as the norm. Mountains are then higher and sea-floors lower than the surface of this ellipsoid. (An ellipsoid is the regular geometric shape obtained by revolving an ellipse round one of its axes.)