14 Machine Trades Print Reading Copyright Goodheart-Willcox Co., Inc. Goodheart-Willcox Publisher Six principal view surfaces of a third-angle drawing are flattened, like a two-dimensional drawing. Figure 2-4 Third-angle projection symbol Goodheart-Willcox Publisher Visualizing an object in first-angle projection. A—Viewing planes divided into four quadrants with the first quadrant highlighted. B—An object in a glass box showing first-angle projection. The three primary views project to the opposite sides of the glass surfaces. C—This symbol indicates a first-angle projection. Figure 2-5 A B C