Randomly generate automata

cells.py

#!/usr/bin/env python

# commented version of a gist from @thenoviceoof

import os
import time
import random

# capture the screen size and find the middle-ish pixel
rows, columns = os.popen('stty size', 'r').read().split()
columns = int(columns)
middle = columns/2

# init a state vector as wide as your screen
state = [0]*columns
state[middle] = 1

# state 30
# 30..  not sure what oof meant by that
# aha!  he says he meant the venerable rule 30: http://en.wikipedia.org/wiki/Rule_30
# this dict is how new states are formed from the old
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():
    # this recomputes the "n" dict above
    l = [(0,), (1,)]
    for i in range(2):
        # (0,) + (0,) = (0,0)
        # build up "l," the list of tuples
        # eventually contains all permutations of [0,1]p3 like (0,1,0), (1,1,0), etc..
        l = [a+(0,) for a in l] + [a+(1,) for a in l]
        
    d = dict()
    for a in l:
        # assign a random value to each permutation
        d[a] = random.randint(0,1)
    return d

while 1:
    # the visuals - zeros in the state vector are spaces, ones will be #
    print "".join([{0:" ", 1:"#"}[c] for c in state])
    
    # next line of state is initialized
    next_state = [0]*columns
    # each element dependent on past value of itself and values of prev and next elements
    for i in range(columns-2):
        # check the n dict to determine the result of a permutation
        next_state[i+1] = n[tuple(state[i:i+3])]
    state = next_state

    # 40% chance of flipping a random value in the state vector
    if random.random() < 0.4:
        i = random.randint(0,columns-1)
        state[i] = {0:1, 1:0}[state[i]]

    # 1% chance of changing the state-maker
    if random.random() < 0.01:
        n = rand_machine()

    # let's go
    time.sleep(0.01)

I believe I meant http://en.wikipedia.org/wiki/Rule_30 by State 30?

@thenoviceoof aha, excellent!