"Lucy and Lily, a game of geometry"-a paper by Richard Evan Schwartz (2025Spring Groveslloqium) 

Chapter 4&6 on Trees by Serre (2025Spring DoGGs)

Chapter 2 on An overview of Patterson-Sullivan theory by J.-F. Quint (2024 Fall DoGGs)

Introduction to polygonal billilards (2024 Spring GGTDS)