Click Green Flag. Adjust the three slider variables, Bulge IN or OUT; Pen Size; and Size of Bulge. Space Bar will hide sliders. Press S key to stop all.
I changed the black grid to a rainbow grid. I added a Pen Size variable. I added Press S key to freeze the design (so you can take a screenshot & add it to a file). I renamed two variables to Bulge Size and Bulge IN (- number on slider) or OUT (+ number on slider).
