Kenison, Ervin, Bradley, Harry Cyrus, 1871-1936 · New York : The Macmillan Company · leaf 42
ns up and down, right and left, both of which areshown by the ^projection, rarely trouble the student. Thedirections forward and backward, however, which are alwajrsshown by the //-projection, often cause confusion. This diffi-culty should disappear by considering the method of projectinga solid… … Fig. 41. the observer is behind one which is nearer; so that the direc-tion from front to back is away from the observer. This isshown in Fig. 41 by the arrowA, which points away from theobserver, and therefore pointsbackward. The arrow B in thisfigure points toward the ob-server, and is pointing…
Geometry, Descriptive
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