import turtle
import random


def rule1(xold,yold):
    x=0.5*xold +1
    y=0.5*yold +1
    return (int(x),int(y))

def rule2(xold,yold):
    x=0.5*xold +1
    y=0.5*yold +500
    return (int(x),int(y))

def rule3(xold,yold):
    x=0.5*xold +500
    y=0.5*yold +500
    return (int(x),int(y))


turtle.speed("fastest")
turtle.up()

x=y=0

rules=[rule1,rule2,rule3]

for i in range(50000):
   r=random.randint(0,2)
   x,y = rules[r](x,y)
   turtle.goto(x-500,y-500)
   turtle.dot(1)


input("done")