Schmidt Arrangement

This picture drawn by Katherine Stange shows what happens when we apply fractional linear transformations $z \mapsto \frac{a z + b}{c z + d}$ to the real line sitting in the complex plane, where $a,b,c,d$ are Eisenstein integers that is, complex numbers of the form $m + n \exp(2 \pi i/3)$ with $m,n$ being integers.

Algebraic Numbers

This is a picture of the algebraic numbers in the complex plane, made by David Moore based on earlier work by Stephen J. Brooks. Algebraic numbers are roots of polynomials with integer coefficients. In this picture the color indicates the degree of the polynomial.