First, set "Detail". 150 is the recommended number, but depending on the speed of your computer, you may have to go lower or higher. The original project used a detail of about 50. Click the flag, then move the mouse to build a custom rug. If the project runs a bit slow, decrease the detail. If you have a fast computer, try increasing it. Tip: Start with slow movements to get the hang of the program. Tip: As with previous versions of this project, pressing space gives you a... surprize.