Search Loci: Convergence:
Cogito Ergo Sum. "I think, therefore I am."
Discours de la Methode. 1637.
Van Schooten's Ruler Constructions
Solution to Problem III
Problem III: Through a given point C draw a straight line parallel to a given straight line AB.
Construction: Draw from C through A an indefinitely long straight line and put on it AD equal to AC and from D through B make DBE. In that, place BE equal to BD and join CE. I say that it is parallel to AB.