Hey, it is quite good! A good survey of the very basic features, with this one can do good sketches already. Perhaps missing some text functions, but then it would need some additional pages...
I like the way it is presented, compact and precise.
Some little remarks: there is a typo in the draw() explanation, I would drop comma, semi-colon (and the accidental dot) between + - * / as it can be confusing, and elseif must be written in two words. Otherwise, it is excellent.