pp : peppered moth
pP : melanic moth
PP : pure melanic moth
To have a black and a white environment of the same size : the terrain size have to be on 50. To change the size of the terrain, you have to change the value of the terrain size with the slider and push the setup button.
The terrain is totally black if the slide is on 153. So to have 10 % of dark territory, we enter 10% of 153. It's the same with 90% dark territory, but we have to put the slide on 50 to have 50 % of dark territory.