[pstricks] Gradient in two directions

[Christopher Ellison]

>From the examples I've seen, I haven't figured out how to do this---as they 
usually involving a single

Imagine a single vertical strip with a gradient from red to green.  Now, I 
want this vertical strip repeated horizontally as a gradient approaching 
white.  So, the red would approach white...and the green would approach 
white.  Thus, you might say that I am looking for a "double gradient".

Any ideas?  I've look at the pst-slpe documentation but I didn't see what I 
was looking for.