Mathematician, musician, and rhythm gamer. Bronze at IMO, xenharmonic album underway, and Division 4 on FFR. What else can I say?
Mathematics
Q&A for people studying math at any level and professionals in related fields
MathOverflow
Q&A for professional mathematicians
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
3D Printing
Q&A for 3D printing enthusiasts
Super User
Q&A for computer enthusiasts and power users
Stack Overflow
Q&A for professional and enthusiast programmers
Music: Practice & Theory
Q&A for musicians, students, and enthusiasts
Artificial Intelligence
Q&A for people interested in conceptual questions about life and challenges in a world where "cognitive" functions can be mimicked in purely digital environment
Web Applications
Q&A for power users of web applications
Mathematics Educators
Q&A for those involved in the field of teaching mathematics
Spanish Language
Q&A for linguists, teachers, students and Spanish language enthusiasts in general wanting to discuss the finer points of the language
German Language
Q&A for speakers of German wanting to discuss the finer points of the language and translation
Code Golf
Q&A for programming puzzle enthusiasts and code golfers
Worldbuilding
Q&A for writers/artists using science, geography and culture to construct imaginary worlds and settings
Puzzling
Q&A for those who create, solve, and study puzzles
Proof Assistants
Q&A for mathematicians and computer scientists who develop and use proof assistants
Area 51
Q&A for proposing new sites in the Stack Exchange network
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites