I actually don’t have flash here so this is based on a
quick skim of your code, but instead of “var angle =
random(360);” (which I presume generates an random angle that
you use to spreads your point around the middle of the center), you
could generate a random angle from 1 to 89 instead.

Then when it comes to plot the points, you could add on an
offset depending on what quadrant the point is supposed to appear
in:

For the first quadrant it would be an offset of 0, so

1+ random( 89) + 0 would equal random angles from 1 to 89

Then for the next quadrant it would be an offset of 90:

1+ random( 89) + 90 would equal random angles from 91 to 179

The next quadrant it would be an offset of 180:

1+ random( 89) + 180 would equal random angles from 181 to
269

And finally, the last quadrant it would be an offset of 270:

1+ random( 89) + 270 would equal random angles from 271 to
359

I set the random angle going from 1 to 89, rather then 0 to
90, to avoid angles generated at 0,90,180, and 270 degrees... which
would appear right on the border.