p1 = Point(0,0,0)
p2 = Point(800,0,0)
l1 = Line(p1,p2)
w1 = Wall(l1,20,300)
p3 = Point(0,1000,0)
p4 = Point(800,1000,0)
l2 = Line(p3,p4)
w2 = Wall(l2,20,300)