File:Gray square illusion.png

Gray square illusion -- reproduction of Image:Optical.greysquares.arp.600pix.jpg in POV-Ray by PaulStansifer.

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Code used:

#include "colors.inc"
#include "woods.inc"

camera{
  location <5,5,-5>+<0.5,0,0.5>
  look_at  <0,0,0>+<0.5,0,0.5>
  right x*image_width/image_height
}

// value of shadowed white area = 0.8 * 0.4
// value of lit black area = 0.2 * (0.4 + 0.6*2.0)

box{
  <-1.985,-0.01,-1.985> <2.985,-0.5, 2.985>
  
  pigment{
    checker rgb 0.2 rgb 0.8
  }
  finish{
    ambient 0.4
    diffuse 0.6
    specular 0
    phong 0
    brilliance 0
  }
}

#local WoodWidth = 0.25;
box{
  <0,0,0.015> <-WoodWidth, -0.5, 5+WoodWidth>
  texture{ T_Wood1 }
  translate <-2.5, 0, -2.5>
  rotate y*0
  translate <0.5,0,0.5>
}
box{
  <0,0,0.015> <-WoodWidth, -0.5, 5+WoodWidth>
  texture{ T_Wood1 }
  translate <-2.5, 0, -2.5>
  rotate y*90
  translate <0.5,0,0.5>
}
box{
  <0,0,0.015> <-WoodWidth, -0.5, 5+WoodWidth>   
  texture{ T_Wood1 }
  translate <-2.5, 0, -2.5>
  rotate y*180
  translate <0.5,0,0.5>
}
box{
  <0,0,0.015> <-WoodWidth, -0.5, 5+WoodWidth>
  texture{ T_Wood1 }
  translate <-2.5, 0, -2.5>
  rotate y*270
  translate <0.5,0,0.5>
}


cylinder{
  <2,0,2> <2,2.5,2>, 0.7
  
  pigment{ rgb <0,0,1> }
}

light_source{
  <5,5,5>
  color 2.0
      
  area_light 1.5*x, 1.5*y, 10, 10
  adaptive 1
  circular
  orient
}

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