isosurface{ // ------------------------------------------------------------

  function {  sqrt(x*x + y*y + z*z) - 0.9
              + sin(12*atan2(x, z))*sin(8*atan2(y, sqrt(x*x + z*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<0.3,1.0,0.1>}
           finish { phong 1}
	  }
  scale 1.00
  rotate <-25, 25, 0>
  translate <-0, 1.3, 0>
} // end of isosurface -----------------------------------------------------