One problem with many of these dot representations is that the dots occlude other dots.  This is particularly a problem when zoomed out.  This visually overrepresents the dots drawn last.<p>For example, look at a blown up version of this area:<p><a href="http:&#x2F;&#x2F;i.imgur.com&#x2F;XA9IDqy.png" rel="nofollow">http:&#x2F;&#x2F;i.imgur.com&#x2F;XA9IDqy.png</a><p>Blue and red might be equal in numbers in this area, but because blue occludes red, unless you zoom in, all you see is a predominately blue region.<p>A quick solution is to put all dots in a list, shuffle the list, then draw each dot -- instead of drawing all of one color at a time.