scatter and Polygon

Hi,

how can I draw the scatter squares in front of the Polygon?

from pylab import *
x,y = zip(*randn(10,2))
ax=subplot(111)
xRange=(-10,10)
yRange=xRange
poly = Polygon([(xRange[0], yRange[0]), (xRange[0], yRange[1]), (0, yRange[1]), (0, yRange[0])],
           facecolor='0.7', edgecolor='0.6', alpha=0.0)
ax.add_patch(poly)
ax.scatter(x,y, color="b", s=150, marker="s", alpha=0.2)
show()

Regards,
wr