Simon loves looking at things geometrically. Even when solving word problems, he tends to see them as a graph. And naturally, since he started doing more math related to machine learning, graphs have occupied an even larger portion of his brain! Below are his notes in Microsoft Paint today (from memory):

Slope of Line:

Steepness of Curve:

An awesome calculator Simon discovered online at desmos.com/calculator that allows you to make mobile and static graphs:

Yesterday’s notes on the chi function (something he learned through 3Blue1Brown‘s videos on Taylor polynomials):

Simon following The Math of Intelligence course by Siraj Raval: