This blog is written and maintained by Sachi Hashimoto. She recently finished her first year in graduate school at the University of Michigan, and is taking two years off to help launch Proof School, as member of the math faculty. Sachi studies algebraic geometry, spends her summers working and dancing at Mathcamp. Maybe one day it will be updated more frequently again. In the meantime, feel free to email her at shashimoto(at)proofschool(dot)org with questions or corrections.