triangular prism

A triangular prism is a three-sided prism; it is a polyhedron made of a triangular base, a translated copy, and 3 faces joining corresponding sides. A right triangular prism has rectangular sides, otherwise, it is oblique. A uniform triangular...

square pyramid

A square pyramid is a pyramid having a square base. If the apex is perpendicularly above the center of the square, it will have C4v symmetry.


A superellipse, or Lamé curve, is a closed curve resembling the ellipse, retaining the geometric features of semi-major axis and semi-minor axis, and symmetry about them, but a different...


An ellipse is a curve in a plane surrounding two focal points such that the sum of the distances to the two focal points is constant for every point on...

deltoid curve

A deltoid curve, deltoid, tricuspoid or Steiner curve, is a hypocycloid of three cusps. In other words, it is the roulette created by a point on the circumference of a circle as it...


A cardioid, heart-like form, is a plane curve traced by a point on the perimeter of a circle that is rolling around a fixed circle of the...


An astroid is a particular mathematical curve: a hypocycloid with four cusps. Specifically, it is the locus of a point on a circle as it rolls inside a fixed circle...

Archimedean spiral

The Archimedean spiral, or arithmetic spiral, is a spiral named after the 3rd century BC Greek mathematician Archimedes. It is the locus of points corresponding to the locations over time of a...


An arbelos is a plane region bounded by three semicircles connected at the corners, all on the same side of a straight line (the baseline) that contains their diameters.


An annulus, or little ring, is a ring-shaped object, a region bounded by two concentric circles. also: little ring, anulus, anuli, annuli


A pentagram, pentalpha, pentangle or star pentagon, is the shape of a five-pointed star drawn with five straight strokes. also: pentalpha, pentangle, star pentagon

star polygon

A star polygon is a type of non-convex polygon. A regular star pentagon, {5/2}, has five corner vertices and intersecting edges. also: concave decagon