This is a technique called a lissajous. (look it up, if you really care) I see it as a symmetrical representaion of the sound as it happens. The virus unison function must pop the sound out of phase, 90 degrees, thus forming these brilliant and incredibly organic shapes.
http://www.youtube.com/watch?v=Q_kYHBsfPxc
Anyhow, let's see a one voiced anal log do this. Ha! Maybe if it's fed through the virus. (Analog through the virus filters sounds amazing, btw)