isosurface{ // ------------------------------------------------------------
  function{  
            sqrt( x*x + y*y + z*z ) - 0.9
            + sin( 12*atan2(x, z) )*0.1
          }
  threshold 0
  accuracy 0.0001
  max_gradient 5
  contained_by {box {<-1,-1,-1>, < 1, 1, 1>}}
  //open

  texture{ pigment{ color rgb<1,0.9,0.0>}
           finish { phong 1}
	  }
  scale 0.85
  rotate <-25, 25, 0>
  translate <-0, 1.2, 0>
} // end of isosurface -----------------------------------------------------