# In your code, def clear(): means you are defining a function named clear.
# We have to call the function for it to work. By having the function outside of our main code
# we can call this function from anywhere in our program.
def clear():
    """Turn all LEDs off."""
    for i in range(NUM_LEDS):    #At the start of the code, a variable NUM_LEDS = 12 tells the code we have 12 LEDs
        np[i] = (0, 0, 0)        #np (neopixel) [i] the current value of i (from 0 to 11) for NUM_LEDS = 12 
        print (i)                #prints current value of i to Thonny output.
    np.write()                   #writes (0, 0, 0) to currently selected aRGB (defined by current value of i)

# fill is a function to set the LED colour.
# color is a built in python variable that holds an RGB value.
# when you call the fill function (fill(color)) you have to set the value of color.
# Ex: fill((255, 0, 0)) will set all LEDs red. 'fill' sets all LEDs, not just selected LEDs.
def fill(color):
    """Set every LED to the same colour."""
    for i in range(NUM_LEDS):
        np[i] = color
    np.write()