Pygameでラングトンの蟻（Langton's Ant）

描いてみただけ。
ソース

ちょうてきとう。
# -*- coding: utf-8 -*-
import sys
import pygame
from pygame.locals import *

FPS = 30
width, height = 800, 600

BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
RED = (255, 0, 0)

pygame.init()
screen = pygame.display.set_mode((width, height))
clock = pygame.time.Clock()

R = (4, 4)
W, H = R
swidth = width / W
sheight = height / H
sBLACK = 0
sWHITE = 1
state = [[0 for _ in range(sheight)] for _ in range(swidth)]

class Ant:
    def __init__(self, x, y, direction=(0, -1)):
        self.pos = (x, y)
        self.direction = direction

ant = Ant(swidth/2, sheight/2)

while 1:
    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()
            sys.exit()

    for i in range(100):
        drawpos = map(lambda x: x[0]*x[1], zip(ant.pos, R))
        pygame.draw.rect(screen, RED, Rect(drawpos, R))

        cx, cy = ant.pos
        dx, dy = ant.direction
        if sBLACK == state[cx][cy]:
            state[cx][cy] = sWHITE
            ant.direction = (dy, -dx)
            color = RED
        elif sWHITE == state[cx][cy]:
            state[cx][cy] = sBLACK
            ant.direction = (-dy, dx)
            color = BLACK

        drawpos = map(lambda x: x[0]*x[1], zip(ant.pos, R))
        pygame.draw.rect(screen, color, Rect(drawpos, R))
        ant.pos = map(sum, zip(ant.pos, ant.direction))
        nx, ny = ant.pos

        if nx < 0:
            ant.pos = (swidth-1, ny)
        elif nx >= swidth:
            ant.pos = (0, ny)
        if ny < 0:
            ant.pos = (nx, sheight-1)
        elif ny >= sheight:
            ant.pos = (nx, 0)

        drawpos = map(lambda x: x[0]*x[1], zip(ant.pos, R))
        pygame.draw.rect(screen, WHITE, Rect(drawpos, R))

    pygame.display.flip()
    clock.tick(FPS)
答え合わせ

こちらのほうがはるかに簡潔。
Langton's ant - Rosetta Code