Wasn't it Bill DeWitt who wrote:

>>     Where did the second (internal) sphere come from?

It's quite a neat optical illusion. The three stretched light grey
hexagons at the front of the sphere just happen to look the same shape
that you would see if there were a small sphere inside the larger one.

Here's a simplified source file that maintains the effect. (So that
people who don't have "GraphPaper.mcr" can play with the source code,
and won't be distracted by all the other stuff that are not actually
involved in the illusion.

background {rgb 1}
camera {location <0,10,20 > look_at 1 angle 40}
light_source {<40, 80, 40>, colour rgb 1}
sphere  { 1,5
    pigment { hexagon
      rgbt 1,
      rgb <1,0,0>,
      rgb <0,1,0>,
     scale 0.5
    }
}


To dispel the optical illusion, try replacing the "rgbt 1" with "rgb 1".
The sphere is now opaque, and the three patches that looked like an
inner sphere are now clearly seen to be on the surface of the outer
sphere.


-- 
Mike Williams
Gentleman of Leisure

Post a reply to this message