# Tk_Slither2.py

# Tk_Slither2.py

from Tkinter import *
import random
import time

HEIGHT=500
WIDTH=800
POPULATION=80

def randomColor():
    return "#%03x" % random.randint(0, 0xFFF)

def ball(x, y, r=10):
    return canvas.create_oval(x-r, y-r, x+r, y+r, fill=randomColor())

root=Tk()

canvas=Canvas(root, width=WIDTH, height=HEIGHT, bg="white")
canvas.pack()
root.wm_title("Slither2")

class Cv():
    x=y=xm=ym=loc=0
cv=Cv()

r = 40
locations = []
for x in range(r,WIDTH-r,r):
    for y in range(r,HEIGHT/2-r,r):
        locations.append([x,y])
0
balls=[]
for count in range(POPULATION):
    balls.append(ball(400,400))
balls.sort(reverse=True)

def slither():
    while 1:
        if not cv.loc:
            cv.loc=locations[:]
            random.shuffle(cv.loc)
            cv.loc=cv.loc[:20]
            cv.loc.sort(reverse=True)
        x,y=cv.loc.pop()
        if x != cv.xm:
            cv.xm = x
            break
    cv.ym = HEIGHT/2+y*polar
0
polar = -1
slither()
track = 0
while 1:
    if track > 200:
        track=0
        slither()
        polar *= -1
    track+=1
    for t in range(POPULATION):
        objx,objy=canvas.coords(balls[t])[:2]

        if (t == 0):
            xv=0.09 * (cv.xm-objx)
            yv=0.09 * (cv.ym-objy)
        else:
            xv=0.09 * (cv.x-objx)
            yv=0.09 * (cv.y-objy)
        cv.x,cv.y=objx,objy
        canvas.move(balls[t], xv, yv)
    root.update()