<P> In shape analysis, the topological skeleton or medial axis of a shape is a thin version of that shape that is equidistant from its boundaries . </P> <P> In Euclidean geometry, parallel lines (lines that never intersect) are equidistant in the sense that the distance of any point on one line from the nearest point on the other line is the same for all points . </P> <P> In hyperbolic geometry the set of points that are equidistant from and on one side of a given line form an hypercycle (which is a curve not a line). </P>

The set of all points equidistant from the endpoints of a segment