Newton's Method of Drawing the Cissoid of Diocles
This Demonstration shows Newton's method of drawing the cissoid of Diocles. The length of and the point are fixed. As you drag on the straight line , is kept perpendicular to . The midpoint of traces out the cissoid.
According to , the method uses two line segments of equal length at right angles. If they are moved so that one line always passes through a fixed point and the end of the other line segment slides along a straight line, then the mid-point of the sliding line segment traces out a cissoid of Diocles.
 J. J. O'Connor and E. F. Robertson. "Cissoid of Diocles." (Jan 1997) www-history.mcs.st-and.ac.uk/Curves/Cissoid.html.