Though graphical, this demo doesn't use binary image files such as GIF, JPEG, and PNG, but consists only of text data.
This version doesn't even require the capability to render SVG but is less fine. An XHTML+SVG version is recommended if your browser can render SVG.
You see 2 disks ● ● .
First of all, close (or cover with your hand) your left eye, and look at the left blue disk ● by your right eye.
Far apart from the display at first, get close to the display slowly and slowly keeping the blue disk ● at the center of the view of your right eye.
If another yellow disk ● disappears on the way to the display, you also have a blind spot, and it's so big that the whole disk ● vanishes!
Disapearing completely, now, what do you see at the place that the disk ● took? White? Black?
If the place is filled by the same background color as that around the disk ●, your "seeing" is nice.
Next, close your right eye and look at the right yellow disk ● by your left eye, and get close gradually. You will have an experience of the same kind.