====== exercise: a switch which alternates between green and red ======

Make a circuit which can alternate between green and red LEDs depending on the position of a switch.

When the switch is down (on), the green LED should light up. When the switch is up (off), the red LED should light up.

Because there will be two different circuits depending on the position of the switch, you need to use two resistors: one for the LED in each circuit.