Move around the dots by pressing down the mouse and holding it down, then move the mouse around.
I give HUGE credit to @TheLogFather for having the pen RGB with opacity (like "opaquacity" (opaque) or translucency), and the axis-aligned tri-filler with no overlapping lines. 6/1/15: I realized that in around the middle of the triangle, some lines were overlapping, mostly since when you divide a number by another number, there can be a remainder, and because of this I had to compress everything into one loop with an if statement, showing if the lines start going below point B, then the lines will change.