2-state 3-symbol State Machine with Two Stacks, same as Wolfram's (2,3) Universal Turing Machine

w23tm-2stacks.py

from time import sleep

# (state,symbol) => (state,symbol,head)
delta = {(0,0):(1,1,+1), (0,1):(0,2,-1), (0,2):(0,1,-1),
         (1,0):(0,2,-1), (1,1):(1,2,+1), (1,2):(0,0,+1)}
ds = {0: ' ', 1: '.', 2: '*'}

tlen = 80
state, stack, stackT, head = 0, [0] * tlen, [], int(tlen / 2) - 10

while 0 <= head <= tlen:
    for _ in range(head): stackT.insert(0, stack[0]); stack = stack[1:]
    state, symbol, headN = delta[(state,stack[0])]
    stack = stack[1:]; stack.insert(0, symbol)
    for _ in range(head): stack.insert(0, stackT[0]); stackT = stackT[1:]
    head += headN
    for s in stack: print(ds[s], end='')
    print()
    sleep(0.005)