Video: Link

Documentation: Link

It's a blueprint system for planting and mowing grass. You can plant three types of grass, or expand more. Then turn on the

lawn mower and cut them off. 

You can use control splines to limit the range of grass growth. You can also adjust the number, size, and distance of the lawn mower blades to get the right lawn mower for you.

If the overview level is completely white when you open your project, Enable 'Extend Default Luminance...' in your project settings.