This section is from the book "The American House Carpenter", by R. G. Hatfield. Also available from Amazon: The American House Carpenter.
Cast rays from a and b (Fig. 447), and find the point c as in the previous examples; from d draw the ray de, and from e the horizontal line ef; tangical to the curve at g and h draw the rays gj and h i, and from i and j erect the perpendiculars il and jk; from m and n draw the rays mf and nk, and trace the curve between k and f; cast a ray from o to p, a vertical line from p to s, and through s draw the horizontal line s t; the shadow as required will then be completed.

Fig. 448.
Fig. 448 is an example of the same kind as the last, with all the shadows filled in, according to the lines obtained in the preceding figure.
Figs. 449 and 450 are examples of the Tuscan cornice. The manner of obtaining the shadows is evident.
 
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