Sine and cosine and tan aka Trigonometry again, from Better Explained.
Bonus! Online version of the fantastic book, Calculus Made Easy - sample quote - "Being myself a remarkably stupid fellow, I have had to unteach myself the difficulties, and now beg to present to my fellow fools the parts that are not hard. Master these thoroughly, and the rest will follow. What one fool can do, another can".
4. Two dimensional lists (or arrays) for remembering pixels.
Sol LeWitt was a pioneer in minimalist and conceptual art, drawing up rules or algorithms that then could be carried out by anyone - "The system is the work of art; the visual work of art is the proof of the system"