Here are some visualizations I have created in my research:

Apollonian circle packings

The Apollonian circle packing corresponding to the Descartes quadruple (-23, 48, 49, 52). This image can be easily generated with the code in Apollonian. The local-global conjecture is false for every residue class modulo 24 in this packing.

Fundamental domains

Fundamental domains for every Shimura curve of genus 2. This list was enumerated by John Voight, and the corresponding domains were computed with the code in Fundamental domains for Shimura curves.