Visit scratch.mit.edu/projects/25468311/remixes/ to see CS First projects that began with this starter project. Hit the green flag to start, then push down on you mouse to start painting. To change the color, hit the right arrow. To change the shape of the graffiti, hit the space button. To clear, either hit the green flag, or the erase button.
Thanks cs first. Shout-out to Alondra for testing it!