And since the image is abstract, both cross- and parallel-viewing work, giving different effects.
<FVdP-Fusion1.jpg>
With anaglyph glasses on:
-when you start looking from the top left corner you see a plane with a
hole and a button in it
-when you freeview (with glasses still on) you see a ramp starting on
the left and the button no longer in the hole
conFUSING isn't it?