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"If the cylinder A were to be developed a right section as at S—S would have to be taken, whose stretchout would be a straight line. If the cutting planes were taken at uniform distances apart, or at random, the elements would not be spaced uniformly on the stretchout but would be found as they project on the turned section of S—S." —French, 1911

Two Cylinders with Axes Not Intersecting

"If the cylinder A were to be developed a right section as at S—S would have to be taken, whose…