Once you click flag, just sit back and watch. Click the "c" key to change the background to black. I feel that this project looks better in black background since the lines fully disappear. Also, turbo mode looks awesome in black background (because of the same reason). White background looks nice if you are in normal mode and not turbo.
This is a remix of the first project i had on this account. Remix all you want, like and love as well. Also, I'd like to mention ecker00 because I got the logic for the disappearing lines from his project Butterfly Painter One.