/* Shader description goes here */
surface
ST_2circle(float    Kfb = 1)
            
{
  
  
color surfcolor = (0.6,0.0,0.6);
color surfopacity = 1;
  
  
float circle1;
float circle2;
  
circle1 = sqrt( (s -.6) * (s -.6) + (t -.5) * (t -.5) );
circle2 = sqrt( (s -.7) * (s -.7) + (t -.5) * (t -.5) );
if ( circle1 < .4 && circle2 >.4 )
    surfcolor= color (0.0,0.0,0.8);
  
Oi = Os * surfopacity;
  
  
Ci = Oi * Cs * surfcolor  ;
}