Click here to see the SAS code.
Click here to see the example.

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See my blog for more information!


I borrowed this idea from
http://yihui.name/en/2008/09/to-see-a-circle-in-a-pile-of-sand/
and implemented it in SAS ...

First I generate a bunch of normally distributed x/y coordinates
using SAS' rannor (by using the Normal distribution, they are 
clustered more densely near 0,0).

Then I generate x/y points along the edge of a circle, with 
radius=.75 and center at =0,0.

I combine the 2 data sets, and randomize the order (so it is 
difficult to determine that there is a circular pattern "hidden"
in the data just by looking at it.

I first plot the data with solid-colored markers -- but the 
markers are so densely-packed together that the "solid black"
obscures the hidden circle pattern.

Next, I use the new SAS 9.3 alpha-transparency so that the 
markers are somewhat transparent, but when multiple markers 
overlap, then the addative effect of the transparent markers
makes them appear darker -- the "hidden" circle can now be
easily seen! :)

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