Sorry but I can not write well in English.
For "policy" mean by logic.
In my opinion, the first thing to know of any maps, you understand what needs to create and equip themselves with examples from which to learn the logic, before you throw random graphics.
As to the sentence that you did not understand:
Furthermore autotile you used to make the leaves of trees, makes evil
I meant that autotile that you used to simulate the leaves of trees not on that impression.
To me, you'd better have the trees in this way:
I hope you understood what I meant