how brush texture helps photoshop painting

here is a digital drawing i did years ago. it's very simple in process, but turn out really nice. i'm showing some of the process work.

first, i got some blocks going on. they are just fine color squares.

and very ez, after i put on a few strokes of brushes, it looks just like some kind of grass. after this step, i had some hardcore work on color to make sure all the colors works well together.

those little building, i draw them in 1px brush. now i figure i have some perspective issue with those tiny buildings, but doesn't matter, you can't see it. lol