"Divide the circumference into a number of equal parts, drawing the radii and numbering the points.…

Illustration of 16 concentric congruent ellipses that are rotated about the center at equal intervals…

Illustration of 2 concentric congruent ellipses that are rotated about the center at 90°. The ellipses…

Illustration of 4 concentric congruent ellipses that are rotated about the center at equal intervals…

Illustration of 8 concentric congruent ellipses that are rotated about the center at equal intervals…

Mexican jar with spiral design sketched in the American Museum of Natural History in New York.

An illustration showing how to construct a spiral with compasses and four centers. "Given the pitch…

An illustration showing how to construct an arithmetic spiral. "Given the pitch p and angle v, divide…

"If B and C are points in the spiral and the ratio of AC to AB be given, the intermediate point D may…

A graph showing a logarithmic or equiangular spiral. The spiral is created in polar coordinates (r,Θ)…

A helix spiral generated by revolving about an axis at an angle less than 90 degrees. This generates…

"This class of spirals may be generated by unwinding a perfectly flexible but inextensible chord from…

Spiral with lines AB and CD drawn on piece of paper shown flat.

Spiral with lines AB and CD drawn on piece of paper and rolled into a cylinder to form spiral running…