Turing machine from https://fr.wikipedia.org/wiki/Machine_de_Turing#Exemple

result.bash

➜  ~  python turing.py
 1) idx=0 on [1, 1] with state=e1
 2) idx=1 on [0, 1] with state=e2
 3) idx=2 on [0, 1] with state=e2
 4) idx=3 on [0, 1, 0] with state=e3
 5) idx=2 on [0, 1, 0, 1] with state=e4
 6) idx=1 on [0, 1, 0, 1] with state=e5
 7) idx=0 on [0, 1, 0, 1] with state=e5
 8) idx=1 on [1, 1, 0, 1] with state=e1
 9) idx=2 on [1, 0, 0, 1] with state=e2
10) idx=3 on [1, 0, 0, 1] with state=e3
11) idx=4 on [1, 0, 0, 1] with state=e3
12) idx=3 on [1, 0, 0, 1, 1] with state=e4
13) idx=2 on [1, 0, 0, 1, 1] with state=e4
14) idx=1 on [1, 0, 0, 1, 1] with state=e5
15) idx=2 on [1, 1, 0, 1, 1] with state=e1
Final 16) 2 on [1, 1, 0, 1, 1]

turing.py

# -*- coding: utf-8 -*-

from __future__ import print_function

class Ruban(list):

    def __init__(self, l):
        super(Ruban, self).__init__(l)

    def __getitem__(self, i):
        if len(self) <= i:
            return 0
        else:
            return super(Ruban, self).__getitem__(i)

    def __setitem__(self, name, val):
        if len(self) == name:
            self.append(val)
        else:
            super(Ruban, self).__setitem__(name, val)

def e1(l, i):
    if l[i] == 0:
        return None, i
    else:
        l[i] = 0
        return e2, i+1

def e2(l, i):
    if l[i] == 1:
        l[i] = 1
        return e2, i+1
    else:
        l[i] = 0
        return e3, i+1

def e3(l, i):
    if l[i] == 1:
        l[i] = 1
        return e3, i+1
    else:
        l[i] = 1
        return e4, i-1

def e4(l, i):
    if l[i] == 1:
        l[i] = 1
        return e4, i-1
    else:
        l[i] = 0
        return e5, i-1

def e5(l, i):
    if l[i] == 1:
        l[i] = 1
        return e5, i-1
    else:
        l[i] = 1
        return e1, i+1

def main():
    l = Ruban([1, 1])
    next = e1
    i = 0

    s = 1
    while next is not None:
        print("%s) idx=%s on %s with state=%s" % (str(s).rjust(2), i, l, next.__name__))
        next, i = next(l, i)
        s+=1
    print("Final %s) %s on %s" % (str(s).rjust(2), i, l))

if __name__ == '__main__':
	main()