 So we have a program that will tell us what time it is. That's useful. What would make it more useful is if we didn't have to run it over and over again to check and see what the time was. But if we could just set it up and let it run and let it continually tell us what time it is right now. To do that, we're going to use a couple of new tricks. The first is a while loop. So here in line three, we see the word while. This is a special word to Python. You can't use it for a variable name. It's a keyword. And to Python, while says, as long as this thing in the parentheses says to keep going, then there's a colon and then an indented section of code. As long as this thing in the parentheses is true, then keep running this indented section of code over and over and over again. In this case, we put the word true in there, which is another special word to Python. So this says that as long as true is true, so for forever, never stop. Keep doing this code in the loop over and over again. Now, computers are really fast, so we want to slow it down a little bit. We'd like to print the time only every once in a while, ideally every second. Luckily, because of the time package that we're working with, we can use a trick that it has called sleep, where we give it a number of seconds. You can see here in the documentation, it explains. You pass it a number of seconds, and this will just pause the program. Whatever it's doing, it'll just stop and meditate and take a deep breath or a few thousand deep breaths, and then after this many seconds, it'll pick back up what it was doing. So what this code does now is it imports our time package and then sets up a loop that's just going to run forever. It pulls the current time in a formatted string. It pulls out the portion that is the time only, and it prints it, and then it sleeps for a second. It waits for a second, and then it does it again. And when we run it, we can see the result. We can see the time occurring, and then once per second it goes back and pulls the new time, pulls out the hour, minute, and second, puts it on the next line of the screen, and keeps going. This is pretty cool. Now we have a clock that we don't have to re-run to figure out what time it is each time we want to know. We can just always look and see what the most recent one is down at the bottom, and we know that that's the time right now. When introducing while loops, we also introduce a new data type. True and false are a data type that's very special. It's called Boolean, and it can only have one of two values. It's either true or it's false, and it's really good at doing things that require logic, checking whether something is the case or is not the case, or checking whether some combination of things is true. Boolean is something that's going to come up a lot in programming. We have some fun examples coming up here in a little bit, but right now this is one of the purest, most simplest things where we say while, true, do this thing, and true will always be true, and so it'll just keep doing that thing forever. We left out an important piece here. If we use a while loop, this program is going to keep running forever. That's not helpful. We're going to want to stop it and start it, especially if we're making changes to it or turning off our computer. To stop a program that's running in the middle, at any time, for any reason, you can type Ctrl C. If you're in the window that the program is running in and you don't like what it's doing or you're done with it, Ctrl C will just kill it wherever it's at. We're going to use that here as our way to stop our clock. With our while loop running forever, if we let it.