A curve with Cartesian equation
In the Formula of the curve given above, the Torus is formed from a Circle of Radius whose center is rotated along a Circle of Radius . The value of gives the distance of the cutting Plane from the center of the Torus.
When , the curve consists of two Circles of Radius whose centers are at and . If , the curve consists of one point (the origin), while if , no point lies on the curve. The above curves have , (3, 1, 2) (3, 0.8, 2), (3, 1, 4), (3, 1, 4.5), and (3, 0, 4.5).
MacTutor History of Mathematics Archive. ``Spiric Sections.''