Look inside, everything is explained there. But the basic agenda is to create a 2d graph... that changes and looks good! You have one line of code to do this, which means that you can only calculate everything using one line to make the line you see on screen right now.
This is not my actual entry... I forgot to save and had to create a different remix. Though, I must say, the destabilizing sine waves do look pretty cool. The actual entry is here: https://scratch.mit.edu/projects/441946232