The controls at the start mean something, but explaining them would take up too much space. If you want to know what they do, look in the Notes/Credits. Just mess with them, and press space when you are done. Be sure to run it in TURBO MODE(hold shift and click the green flag) Because my brother, @jukeylukey, was drawing some cool patterns in scratch, I decided to automate the process.
Straightness- Just determines the maximum amount the lines can turn each pixel. Density- If a line runs into a previous line, it determines how likely it is to stop and go to another location. The lower the number, the more likely it is to fill in the middle solid. Complexity- How many lines there are. If you have 10, it will be a fairly simple pattern. If you make it 100, it will be much more interesting Distance- Whenever a line runs into another line, it goes somewhere else on the screen. Change the distance to determine how far away it can go, and how far away from the center. Make sure distance is less than size. Size- If your size is less than or equal to 200, it will make your entire pattern inside a circle.