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Voiceover: Ok so you've made a few programs, you might be wondering how on earth am I supposed to remember all of these commands is it oval or circle or ellipse? Is it width and height, or is it height and width? Do I have to memorize all of this? Thankfully, no! That's what the computer is for. The thing is, we always have a computer with us when we are programming, and a computer is really good at remembering things, better than we are. So what if we just had the computer remember all the details for us, and we can just use it like a dictionary for programming. Then we can focus on making cool programs, not memorizing a bunch of boring details. That's what we call documentation, a document that explains how to program in a particular language and environment, with examples and gotchas, so if we can't remember the exact details, no worries - we can just look them up! You might think it's boring to read documentation, and you are right - it is kind of boring, it's a lot more fun to write code. But unless you want to memorize absolutely everything (ugh!), you need to learn how to use documentation or be able to code your ideas. Even great programmers don't try to memorize everything. In fact, great programmers are usually some of the best at reading documentation. For example, I'm drawing this smiley face, and I've already drawn the face and the eyes using ellipse, a function I know pretty well. But I have more work to. First, I want to draw the face with thick outlines, like a sticker. I remember that has something to do with stroke, but I don't remember exactly the name, so instead of sitting here and trying to invent it, which could take hours (or infinity), I'll just go to the documentation tab and look around and try and find what I'm looking for. Umm, and I'll look under this coloring category, cause that seems likely, and look at all the functions here, and then finally at the very end, I find stroke weight to change the thickness of lines and outlines. So here we see the function name and the parameters - just one in this case. So what I usually do is start off by just copying that code and pasting it into my code. But I immediately get an error: "thickness is not defined". That's because thickness is a placeholder parameter. It's not a real value, I am meant to replace that with what I actually want it to be, right, so that could be with a number or a variable that refers to a number, so in this case I'll just put a number in. Say, ah, ok, perfect, 10's nice, but we know we can fiddle with that and see. oh that's a little extreme (laughs). that's too small. All right, so go back - 12. Cool! Now there is something really obvious missing in my smily face: the smile. So I basically just want something like this, right... And I can look at that smile and think, well, doesn't look I'd draw by using an ellipse, or line, or rect, cause it's got this curve to it, but it doesn't have any inside. So I think, well, I should check the docs and see if there is some other way to draw a curve like this. So, to the docs machine we go! Scrolling down, scrolling down, and looking around. So I'll check out the shapes category... Aha! The very first entry in shapes is arc, which is used for drawing an arc, which sounds kind of perfect, because that's what the smile is. So this one has a lot more parameters in it. I'll start off by pasting this in here... And remember these are placeholder parameters so we need to replace them with what we think they should be... All right, so x and y, so maybe x and y is where i want it to begin, so we'll say, so our middle is 100 so maybe it will start at 150, and then y is maybe 250, and then width - width sounds like, you know, the width of the arc, so probably a bit less than width of the actual face. So maybe it's 200, and then the height... maybe that's the height from the top of the arc to the bottom, so go, maybe that's 50. Start and stop... Hmm, I don't actually know what those are... Ok, now I'm stuck, because I'm looking at this function and trying to use it, but I don't really understand these parameters. Well, luckily, what you can do is just go back down to the docs and actually click on the function that you are interested in, and it will bring up a program that shows you how to use it, and actually explains the parameters in a lot more detail. So by looking at this, it says, ok, x is the x-coordinate of the center of the ellipse derived from the ark. Okay, so basically it seems like to draw an arc you kinda have to pretend you're drawing an ellipse, but only part of it, and calculate everything based on that. So the x and y zap to the center of that pretend ellipse we're making, the width and the height are the width and height of that pretend ellipse, and start and stop - those are the ones I didn't know. Start and stop is the angle... ah! Ok, the start angle to start the arc at, in degrees, and stop is where to stop it at, right. And we can actually look at the examples they've done here, so drawing the arc from 1 to 270, that's probably this guy over here, right, because 1 degree to 270 degrees, that's what that would look like. Let's try and change it. There we go, that makes sense, right, because 1 to 180, that's kind of what we want, right, because we want our half arc... Ok, so now I think I understand arc well enough to use it, and let's go back to my smiley... All right, so we're going from 0 to 180, and... we've almost got it. My x amount is off because I didn't realize that x is actually the middle of the ellipse, and is a little bit wide, so let's go make that smaller! Haha! I now have a real smiley face! Thanks to using the docs I was able to do what I wanted much faster. And that's a goal of programming - turn our ideas into reality faster. Remember - use the power of the docs!