# List of Ball objects
D = draw.Drawing(200, 200, origin='center') # define drawing canvas
EARTH_GRAVITY_ACCELERATION = -9.8   # acceleration due to gravity, m/sec^2
BALL_RADIUS = 10  # radius of the ball in pixels

ball_list = []
colors = ['red', 'orange', 'yellow','green', 'blue', 'indigo', 'violet']
for i in range(1,100):
    x  = randint(-90,90)
    y  = randint(-90,90)
    vx = 20*random() - 10
    vy = 20*random() - 10
    c  = randint(0,len(colors)-1)
    ball_list.append( Ball( x, y, vx, vy, colors[c] ) )

def draw_frame():
    for b in ball_list:
        b.draw_ball()
    for b in ball_list:
        b.update_position(0.1) # no gravity
    return D    

for i in range(0,1000):
    D = draw.Drawing(200, 200, origin='center') # erase canvas
    with draw.animate_jupyter(draw_frame, delay=0.05) as anim:
        anim.draw_frame()


# List of Ball objects (with gravity)
D = draw.Drawing(200, 200, origin='center') # define drawing canvas
EARTH_GRAVITY_ACCELERATION = -9.8   # acceleration due to gravity, m/sec^2
BALL_RADIUS = 10  # radius of the ball in pixels

def draw_frame():
    for b in ball_list:
        b.draw_ball();
    for b in ball_list:
        #b.update_position(0.2) # no gravity
        b.animate_step(0.2) # with gravity

    return D    

ball_list = []; # initialize empty list
colors = ['red', 'orange', 'yellow','green', 'blue', 'indigo', 'violet']
for i in range(1,100):
    x  = randint(-90,90)
    y  = randint(-90,90)
    vx = 20*random() - 10
    vy = 20*random() - 10
    c  = randint(0,len(colors)-1)
    ball_list.append( Ball(x, y, vx, vy, colors[c]) )

for i in range(0,1000):
    D = draw.Drawing(200, 200, origin='center' ) # erase canvas
    with draw.animate_jupyter(draw_frame, delay=0.05) as anim:
        anim.draw_frame()