import thread
import time

orient = 1

def fun(w):
    global orient
    if orient > 0:
        w.x += 5
        if w.x > 1000:
            orient = -1
    else:
        w.x -= 5
        if w.x < 0:
            orient = 1

def fun2(w):
    while(True):
        fun(w)
        time.sleep(.1)

def start(w):
    thread.start_new_thread(fun2, (w,))