 rpi-pico-w/upython/blink_gpio.py

Toggle GPIO pin 0 on and off twice a second. Also toggle the on-board LED and print to UART for correlation. You can see this in action e.g. by linking an LED between pin 0 and one of the GND pins of the Pi, and the LED will blink. Circuit:

RPI_PICO_W__1gp0____3gnd
            |       |
            R_2k    |
            |       |
            +-aLEDc-+