A slight variation on Tiny_Box, replacing the background() coloring with fill(), and forgetting about partial opacity. The space savings allows me to use a strokeWeight() call, which I adore so much.
It does end up looking a good bit different than the original Tiny_Box, with the boxes overlaid on top of each other.
I had to specify the width/height of this applet in the applet settings; I'm guessing it doesn't like the use of a variable in the size() call. There are just 192 characters, so entering the numbers directly into the size() call would still keep it under 200.
Manipulating the strokeweight in a standard 3D sphere object, according to a sinusoidal function, makes it look a bit like the sphere is breathing. The z-bouncing is just to make it less boring. :)