Plane Curve -- from Wolfram MathWorld

A plane curve is a curve that lies in a single plane. A plane curve may be closed or open. Curves which are interesting for some reason and whose properties have therefore been investigates are called "special" curves (Lawrence 1972). Some of the most common open curves are the line, parabola, and hyperbola, and some of the most common closed curves are the circle and ellipse.

Wolfram MathWorld - Murat Alper

Flashlights and conic sections – David Richeson: Division by Zero

Spherical Coordinates -- from Wolfram MathWorld

Planar curves - Math Central

Topological Spaces — A Primer – Math ∩ Programming

Topology, a 1961 Eames film for IBM's Mathematica Exhibit

Great circle - Wikipedia

The Complex Plane

The projection point geodesic grid algorithm for meshing the

Tessellation, Penrose Tilings and Infinity – TOM ROCKS MATHS

How can I approximate the area under a curve?

An Attempt on Tree Generation Algorithm, by Hitesh Sahu