This experiment is an extension of the Experiment 1, a blinking led, and will show how a diode is allowing us to make our circuit work (or not work in this case ).
The diode is a special passive component that allows to flow circuit only in one way, the white or gray band on the diode is indicating the flow of the circuit.
The code is the same as the Experiment 1. The sign of the diode is indicating the flow of the current, try to change the orientation of the LED to see the reaction of the LED.
What is the difference of a diode and a LED?
Ask to a fried that has a WMKIT to borrow you a diode and try to add another diode and change the orientation of the two diodes to check how the LED is reacting to the changes.