Randomly generate automata

cells.py

#!/usr/bin/env python

import os
import time
import random

rows, columns = os.popen('stty size', 'r').read().split()
columns = int(columns)
middle = columns/2

state = [0]*columns
state[middle] = 1

# state 30
n = {(0,0,0):0,
     (0,0,1):1,
     (0,1,0):1,
     (0,1,1):1,
     (1,0,0):1,
     (1,0,1):0,
     (1,1,0):0,
     (1,1,1):0,
     }

def rand_machine():
    l = [(0,), (1,)]
    for i in range(2):
        l = [a+(0,) for a in l] + [a+(1,) for a in l]
    d = dict()
    for a in l:
        d[a] = random.randint(0,1)
    return d

while 1:
    print "".join([{0:" ", 1:"#"}[c] for c in state])
    next_state = [0]*columns
    for i in range(columns-2):
        next_state[i+1] = n[tuple(state[i:i+3])]
    state = next_state
    if random.random() < 0.4:
        i = random.randint(0,columns-1)
        state[i] = {0:1, 1:0}[state[i]]
    if random.random() < 0.01:
        n = rand_machine()
    time.sleep(0.5)