Why doesn’t this sketch work? Duplicate and rewrite it so that a circle draws on the canvas. Try to come up with at least two solutions. Add comments to your code explaining your answers.
This sketch doesn't work because variable 'xpos' wasn't declared!
Option 1: Declare 'xpos' before the setup() function, and initialize the value within setup()
Option 2: Declare and initialize 'xpos' at the same time!