 It's the circuit, Python, Parsec, sec, sec, sec, sec. So here's a fundamental thing. How do you read the input of a digital pin? So if you look here on, I've got a Metro Express right here, Metro Express M0. There's a bunch of pins here, general purpose input output pins, GPIO. And sometimes we want to use these as input pins, so we want to be able to read things like switches and buttons. In this case, I have a little button, little breakout board for a button, plugged into ground on one side. And I have it plugged into a digital pin, pin D7 on the board. If you look at my code here, I'm importing the board, which gives me the definitions of what pins are connected to this board and what they do. I'm importing this library called digital IO, and specifically I'm bringing in the sections of the library for digital inputs and outputs for direction, which allows me to say whether I'm going in or out, and pull, which is using an internal pull-up resistor. The next part of the setup I have here is actually just so I can see an LED blink, so we'll ignore that part. So you can see here in this section, I'm setting up one of these pins as the button pin, and I'm calling that a digital input output on D7. I'm setting the direction of that pin to be an input, so it's reading from an, from an external thing inward. And I'm setting that up to use the internal pull-up resistor on the chip. And then my code for doing something interesting with this pin is simply the main loop of the program where it says, while true, what happens? We change the value of that LED to be the opposite of the button value. So when I press that button, the button value is going essentially from high to low, and that's sending my LED from low to high. And this is because of the nature of the pull-up resistor. So there you can see LED value equals not button value, and that means we get to click on the button and light up the LED. Now, of course, you could do many, many more interesting things with it than that, but this is the very beginning sort of foundation of how do I do stuff on my microcontroller, and one of the key things you want to do is interface with an input device from the outside world, and for that we use the digital in. That is your circuit. Python. Parsec.