A lens contained between two cirular arcs of radius R, and centers at O₁ and O₂

The shape of the portion of Kenny McCormick's face visible through his hood is almost a lens, although the arcs are either elliptical or parabolic rather than circular.

In geometry, a lens is a shape comprising two circular arcs, joined at their endpoints. This is a screenshot of a copyrighted movie or television program. ... This is a screenshot of a copyrighted movie or television program. ... Kenny McCormick Kenny McCormick, voiced by Matt Stone, is a fictional character in the animated series South Park. ... In mathematics, an ellipse (from the Greek for absence) is a curve where the sum of the distances from any point on the curve to two fixed points is constant. ... A parabola A parabola (from the Greek: παραβολή) is a conic section generated by the intersection of a cone, and a plane tangent to the cone or parallel to some plane tangent to the cone. ... In Euclidean geometry, a circle is the set of all points in a plane at a fixed distance, called the radius, from a fixed point, called the centre. ... Geometry (from the Greek words Ge = earth and metro = measure) is the branch of mathematics first introduced by Thales (circa 624-547 BC) dealing with spatial relationships. ... In geometry, two sets of points are of the same shape precisely if one can be transformed to another by dilating (i. ... In Euclidean geometry, a circle is the set of all points in a plane at a fixed distance, called the radius, from a fixed point, called the centre. ... The term arc may refer to: A part of a circles circumference (also called a circle segment). ...

References

• "Lens (http://mathworld.wolfram.com/Lens.html)." MathWorld. Accessed on June 13, 2005. which in turn cites
  • Pedoe, D. (1995). "Circles: A Mathematical View, rev. ed.". Washington, DC: Math. Assoc. Amer., ', .
  • Plummer, H. (1960). An Introductory Treatise of Dynamical Astronomy. York: Dover. .
  • Rawles, B. (1997). Sacred Geometry Design Sourcebook: Universal Dimensional Patterns.. Nevada City, CA: Elysian Pub.. . page 11
  • Watson, G. N. (1966). A Treatise on the Theory of Bessel Functions, 2nd ed.. Cambridge, England: Cambridge University Press. .