//--------------------------------------------------------------------------
#declare Ball = //---------------------------------------------------------- 

sphere{ <0,0,0>, 0.07

        texture { pigment{ color rgb<1.00, 0.35, 0.00>*0.9 }
                  finish { phong 1.0 reflection{ 0.10 metallic 0.5} }
                } // end of texture

        scale<1,1,1>  rotate<0,0,0>  translate<0,0,0>
      } // end of sphere ---------------------------------------------------
//--------------------------------------------------------------------------

//-------------------------------------
#declare Ball =
 sphere{<0,0,0>,0.55
      }
#declare Radius0 = 3.0; //Grundradius
#declare NR = 18;//n. of revolutions
#declare NpR= 700;//n. of elements p.r.
#declare Scale=0.83;//n.per revolution
#declare HpR  =0.83;//difference in y p.r.
//-------------------------------------
#local Hd       = HpR/NpR;
#local Scale_p  = pow(Scale,1/360);
#local Scale_pE = pow(Scale_p,360/NpR);
#local Old_S = Scale_pE;
#local Old_H = Hd;


union{
#declare Nr = 0;         // start
#declare EndNr = NR*NpR; // end
#while (Nr< EndNr)
 object{Ball
        translate<Radius0,0,0>
        scale Old_S
        translate<0,Old_H,0>
        rotate<0,Nr * 360/NpR ,0>}
 #declare Nr = Nr + 1;  // next Nr
 #declare Old_S = Scale_pE*Old_S;
 #declare Old_H = Old_H+Hd*Old_S;
#end // ------------ end of loop ----

      texture{ T_Stone7 scale 0.55
               normal{ bumps 0.25 scale 0.25}
               finish{ phong 1 reflection{ 0.03 metallic 0.5} }}

  scale<1,1,1>
  rotate<0,0,0>

  translate<0,0.5,0>
} // end of snail -------------------