I can not explain this effect

[laser1]

I was creating graphics. After I created my last graphic, I rolled my chair backwards to stand. I glanced back at my monitor's screen and I notice that my graphic had an odd effect. The rust colored border appeared be separated from the blue background as if it was a 3D image. I also notices that as I swiveled my chair around, the foreground would remain stationary and the backgrounds would move from side to side. I asked a couple of friend to view the posted image, they both advised that they could see the same effects that I could see. After a period of time, my wife could see some separation of the foreground and the background, but not the movement of the background. She is also unable to view stereograms. It is best seen when view at about three feet from the screen. See if you can see the effect. I posted the graphic at http://goldenwebpage.com/test/test3d.htm