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"The distance of A and B below H is indicated on the V projection. Thus if to A∧h B∧h the perpendiculars A∧h A;and;r and B∧h B∧r be drawn, A∧r B∧r will be the true length of A B." —French, 1911

Construction of Geometric Revolution

"The distance of A and B below H is indicated on the V projection. Thus if to A∧h B∧h the perpendiculars…

"The H projection of the line AB in the space is a line connecting the feet of all the perpendiculars from AB to the plane. These perpendiculars form what is known as the projecting plane. If this projecting plane to be revolved about its H trace, which is the H projection of the line, until it coincides with H, the line will be seen in its true length." —French, 1911

Revolutions into the Plane of Geometric Shapes

"The H projection of the line AB in the space is a line connecting the feet of all the perpendiculars…