This project runs online, try it here! (If you have a MacBook and Safari 10.)
This a simple demonstration of Safari's Force Touch API - a drawing program, of course! This demo is as simple and barebones as you could like: you get a brush and the size of the stroke is based on the pressure you put on your trackpad.
It'll only work on Safari - version 10, I believe, on macOS Sierra. Those are currently the latest versions of Safari and macOS, anyways, so it's not like you have to get some super beta edition to try this!
It should also be relatively obvious that you'll need a MacBook to use this.
More information in the help box in the top left of the program!