pygame.init()

passing_thrus=((240,300),(230,50),(340,218),(348,487), \

(150,200),(278,245),(453,385),(140,238),(240,300))

screen=pygame.display.set_mode((500,500),0,24)

bg=pygame.surface.Surface((500,500),0,24)

clock=pygame.time.Clock()

i=Curve("catmull")

j=Curve("bezier")

i.set_passthru(passing_thrus)

j.set_passthru(passing_thrus)

steps=2

steps1=2

points=i.yieldall(60)

points1=j.yieldall(60)

while 1:

clock.tick(60)

steps+=1

if steps==len(points):

steps=2

steps1+=1

if steps1==len(points1):

steps1=2

bg.fill((255,255,255))

pygame.draw.aalines(bg,(255,0,0),0,list(points[i] for i in range(steps)))

pygame.draw.aalines(bg,(0,0,0),0,list(points1[i] for i in range(steps1)))

pygame.draw.aalines(bg,(255,0,0),0,((0,500),points[steps]))

pygame.draw.aalines(bg,(0,0,0),0,((0,500),points1[steps1]))

for point in passing_thrus:

pygame.draw.rect(bg,(255,0,0),Rect(point[0],point[1],5,5))

screen.blit(bg,(0,0))