This engine generates a smallish map of grass, trees, and rocks. At the start, state how common you want trees and rocks to be scattered across the map. My suggestion for both of these is 8-10. Then, use the arrow keys to move around the map. If you want to set a marker, press space to create a house. Note that trees and rocks cannot be walked past, acting as obstacles, so the more common they are the harder it will be to move around the world. Have fun!
It can be fun to try and navigate to the edge of the map (40 blocks from center, where you will be unable to move any further) with a commonness of 5 for both trees and rocks. For a challenge, try doing this with a commonness of 4 for both trees and rocks (almost impossible)!
