# _Screen.__ini__() - _Screen().setup() bug demo

from turtle import Screen, Turtle, mainloop

class Nim(object):
    def __init__(self):
        self.screen = Screen()
        self.screen.setup(640, 480, -20, 20)
        WIDTH = self.screen.window_width() // 50 # gets wrong value
        print "Should be:", 640 // 50, "but is:", WIDTH
        # here you can look at the consequences:
        self.screen.tracer(False)
        for col in range(20):
            s = Turtle(visible=False)
            s.speed(0)
            s.penup()
            s.shape("square")
            s.shapesize(4, WIDTH/20.)
            packet, element = divmod(col, 5)
            x = (-21 + 11 * packet + 2 * element) * WIDTH
            s.setpos(x, 0)
            s.showturtle()
        self.screen.tracer(True)
        
if __name__ == "__main__":
    nim = Nim()
    mainloop()