Plane Spotting is the perfect guide for anyone interested in identifying aircraft. Learn how to identify different types of aircraft, from commercial airliners to military jets, by their shape, size, and other distinguishing features. Discover the basics of aircraft recognition
From Wikipedia
In mathematics, a plane curve is a curve in a plane that may be a Euclidean plane, an affine plane or a projective plane. The most frequently studied cases are smooth plane curves, and algebraic plane curves. Plane curves also include the Jordan curves and the graphs of continuous functions.