3D

Sierpinski Tetrahedron

Projection Onto A Sphere

Regular Tetrahedron from Four Planes

Regular Tetrahedron from Four Planes (Linear Algebra)

Inversion Through Stereographic Projection

Soddy's Hexlet

Rolling Spheres

Shadow of a Sphere

The Pavillet Tetrahedron

The Pavillet Tetrahedron, Gergonne Line, and Soddy Line

Folding a Triangle

3D to 2D projection

3D to 2D projection (spherical coordinates)

Spirals on a Torus

The Structure of Soddy's Hexlet

Chebyshev Polynomials