Great idea! Well done!
Make the best polygon.
Sometimes there's a bug and the newest point connects to the end which is further away, screwing you over. Sorry!
Here's the PICO-8 forum thread with all of my 1HGJ PICO-8 games.
Fun fact: Two Button Controls was also one of the themes for Ludum Dare 34, where I made my first PICO-8 game Need For Seed: Undergrowth!