"The beginning of the seventeenth century witnessed also a revival of . ...it remained for Girard Desargues... and for Pascal to leave the beaten track and cut out fresh paths. They introduced the important method of Perspective. All conics on a cone with circular base appear circular to an eye at the apex. Hence Desargues and Pascal conceived the treatment of the conic sections as projections of circles. Two important and beautiful theorems were given by Desargues: The one is on the "involution of the six points," in which a transversal meets a conic and an inscribed quadrangle; the other is that, if the vertices of two triangles, situated either in space or in a plane, lie on three lines meeting in a point, then their sides meet in three points lying on a line; and conversely. This last theorem has been employed in recent times by Brianchon, C. Sturm; Gergonne, and Poncelet. Poncelet made it the basis of his beautiful theory of homological figures."
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Florian Cajori, A History of Mathematics (1919)
https://en.wikiquote.org/wiki/Girard_Desargues
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Girard Desargues
(21 February 1591 – September 1661) was a French mathematician, architect and engineer, who is considered one of the founders of . , the , and the Desargues crater are named in his honour.
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