sprite_frames = []
sprite_frame = 0

def setup():
    
    sprite_frames.append( loadImage("frame1.png") )
    sprite_frames.append( loadImage("frame2.png") )
    sprite_frames.append( loadImage("frame3.png") )
    sprite_frames.append( loadImage("frame4.png") )
    sprite_frames.append( loadImage("frame5.png") )
    sprite_frames.append( loadImage("frame5.png") )


def draw():
    global sprite_frame    
        
    image( sprite_frames[sprite_frame] )

    # Option a: The logic for incrementing the variable and checking
    # if it gets too big:
    sprite_frame = sprite_frame + 1
    if sprite_frame >= 5:
        sprite_frame = 0

    # Option b. How to do the same thing in a slightly more compact
    # way:
    sprite_frame = ( sprite_frame + 1 ) % 5

    # Option c. How to do the same thing using a technique such that
    # if you change the number of frames, you wouldn't even have to
    # modify this code:
    sprite_frame = ( sprite_frame + 1 ) % len(sprite_frames)