Generator yield

def draw():
    draw = tcod.console_put_char_ex
    w, h = screen_size()
    for x in range(w):
        for y in range(h):
            c, fg, bg = yield cartesian.Point(x, y)
            fg, bg = (getattr(tcod, str(fg), tcod.white),
                      getattr(tcod, str(bg), tcod.black))
            draw(None, x, y, c, fg, bg)
    yield None