spiral

In mathematics, a spiral is a curve which emanates from a point, moving farther away as it revolves around the point. It is a subtype of whorled patterns, a broad group that also includes concentric objects. Helices Two major definitions of "spiral" in the American Heritage Dictionary are: a curve on a plane that winds around a fixed center point at a continuously increasing or decreasing distance from the point. a three-dimensional curve that turns around an axis at a constant or continuously varying distance while moving parallel to the axis; a helix. The first definition describes a planar curve, that extends in both of the perpendicular directions within its plane; the groove on one side of a gramophone record closely approximates a plane spiral (and it is by the finite width and depth of the groove, but not by the wider spacing between than within tracks, that it falls short of being a perfect example); note that successive loops differ in diameter. In another example, the "center lines" of the arms of a spiral galaxy trace logarithmic spirals.