**Full write-up:** https://www.sebven.com/ctf/2021/08/05/UIUCTF2021-Constructive-Criticism.html

Misc – 408 pts (14 solves) – Chall author: Pranav Goel

Some lo-fi bops on Soundcloud seem to be hiding something. There are cuts in the song where the emphasis jumps from one stereo-channel to the other. Turns out the separate channels in the WAV files are not exactly the same. At some parts they align, and at others they are slightly different. Visualising this difference reveals a bit-like structure which we decode in order to obtain the flag! A unique challenge for sure!

Original writeup (https://www.sebven.com/ctf/2021/08/05/UIUCTF2021-Constructive-Criticism.html).