This sketch visualizes different operators. What it does is gets an x and y coordinate, puts them through a given operator, and uses that value as an outputted color. For example, it might take coordinate 200,-50 and divide them, getting -4 which then gets used as a color. The scale zooms the coordinate grid in and out.
You can use + for addition, - for subtraction, * for multiplication, / for division, pow for exponents, root for roots, log for logs and % for the modulus operator (the remainder of dividing two numbers)