# t_chase.py

# t_chase.py

import turtle
import random

rainbow=[]
def z(r,g,b):
    rainbow.append((r,g,b))
r,g,b=255,0,0
for g in range(256):
    z(r,g,b)
for r in range(254, -1, -1):
    z(r,g,b)
for b in range(256):
    z(r,g,b)
for g in range(254, -1, -1):
    z(r,g,b)
for r in range(256):
    z(r,g,b)
for b in range(254, -1, -1):
    z(r,g,b)
Lc = len(rainbow)

n=300
ccc = Lc/(n+1)

screen = turtle.Screen()
screen.tracer(0,0)
screen.setup(600,600)
screen.title('Chase')
turtle.hideturtle()

chasers = []
for i in range(n):
    chasers.append(turtle.Turtle())

for i in range(n):
    c = '#%02x%02x%02x' % (rainbow[i*ccc])
    chasers[i].up()
    chasers[i].color(c)
    chasers[i].goto(random.uniform(-500,500), random.uniform(-500,500))
chasers[n-1].goto(0,0)
chasers[n-1].shape('circle')
chasers[n-1].shapesize(1)

orbit=2
ppp = range(1,9)
ccc = 0

def chase():
    global orbit, ccc
    if ccc < 290:
        for i in range(n-1):
            angle = chasers[i].towards(chasers[i+1])
            chasers[i].seth(angle)
    zzz = chasers[n-1].pos()
    for z in zzz:
        if abs(z) > 200:
            angle = chasers[n-1].towards(0,0)
            chasers[n-1].seth(angle)
            orbit = random.choice(ppp)
    chasers[n-1].left(orbit)
    chasers[n-1].fd(10)
    for i in range(n-1):
        chasers[i].fd(10)
    ccc = ccc%300 + 1
    screen.update()
    screen.ontimer(chase,0)

chase()