 Let's explore how to add some color to our compositions. This program makes this composition that you've already seen. Now, let's make the background a different color than gray. The easiest way to do that is to use the color picker that processing has. If you go up to the tools menu in processing and you select color selector from the drop-down menu, then this color selector appears. And you can move this little bar around. You can move this little square around. And the color that shows up in this box up here is given to you in numbers down here. This top group is the hue, saturation, and brightness corresponding to this color. Down here is the red, green, and blue value corresponding to this color. And then the bottom one is this color in hexadecimal. The default for processing is to use RGB values, and that's what I usually use. Although I can understand why some people would rather use HSB. Probably if you want to discuss the subtleties of one version or another, you would want to talk to an actual artist. The RGB values are 8-bit colors, so they range from 0 to 255, each one. So for example, this color has this much red, this much green, this much blue in it. And all you have to do is put three arguments into one of the commands that tells you the shading instead of just one argument, and you'll be able to select a color in your program. You can also just type values into here. Here's a nice orange color that I like. It seems to me that if you already know the numbers, you probably don't need the color picker in the first place. But anyway, I just wanted to show you that you can do that. So let's make the background of our composition this nice orange color. Alright, well so to do that, we just have to modify our code and type those numbers in. There we go. There's that color. Now I'm going to change the colors of these two squares, and I'm going to show you some things that we can do with those. So if you want to change the colors of the squares, you have to use the fill command. So let's go ahead and do that. Alright, so the first rectangle is here. We choose the fill first before we draw the rectangle, and let's make it blue. I already looked up these numbers using the color picker, so I know them. And let's make this other rectangle yellow. Now we're going to change the fill from 102, which was kind of a nice gray color, to yellow. I think that should do it. Let's see. Alright, there we are. So if I hadn't written the second fill line in here, they both would have been blue. And the fact that I've got another fill line here telling this circle would be black, and another fill line here telling this one to be gray, then no fill down here telling this one to be transparent. I mean, though I specify the fill for each shape that I've drawn. Let's try to make these colors a little bit transparent. The way you can do that is to add a fourth number to the fill arguments. And that number will be a number that tells you how transparent the shape is going to be. So for example, if I want this blue rectangle to be a little bit transparent, and this yellow one to be a little bit transparent, now when I run, is that a surprising result? It's kind of cool, huh? So the blue rectangle turned kind of purple because you're seeing the red that's in the orange background behind it. And this one, you can see the orange behind it. And you can also see the outline of the other square. So that's just a short little demo of colors and transparency values.