Hi all. Glad you find our site useful. Just wanted to add some context that we just spun up this website this summer, and are currently porting all of our lessons to the Racket programming language. Since we're developing course material to work well with Racket, some lessons might be broken/have typos. This means that this summer, the website is mainly for supporting the students taking the live course. Thanks for understanding. :) -- CS61AS Staff