//--------------------- dimensioni -------
#declare R1 = 0.050; // main radius
#declare R2 = 0.025; // diagonals radius
#declare W = 1.00-R1;// half width(outline!)
#declare H = 2.00;   // height
//--------------------- horizontal frame
#macro Square_Q(R1_, W_ )
union{
 cylinder{<-W_,0,0>,<W_,0,0>,R1_
                    translate<0,0,-W_>}
 sphere  {<0,0,0>,R1_
                    translate<W,0,-W_>}
} #end //-----------------

#macro Square (R10, W0)
union{
 object{ Square_Q(R10, W0) rotate<0,0*90,0>}
 object{ Square_Q(R10, W0) rotate<0,1*90,0>}
 object{ Square_Q(R10, W0) rotate<0,2*90,0>}
 object{ Square_Q(R10, W0) rotate<0,3*90,0>}
     } #end  //---------------------------
//-------------------- vertical elements:
#macro V_Element (R10, R20, W0, H0)
union{
 cylinder {<0,0,0>,<0,H0,0>,R10
                   translate<-W0,0,-W0>}
 // diagonal:
 cylinder{<-W0,0,0>,<W0,H0,0>,R20
                 translate<0,0,-W0+R20>}
 cylinder{<W0,0,0>,<-W0,H0,0>,R20
                 translate<0,0,-W0-R20>}
   } #end //-----------------------------

#macro Element_4 (R11, R21, W1, H1)
union{
object{ Square (R11, W1) }
 //vertical:
object{V_Element(R11,R21,W1,H1)
                 rotate<0,0*90,0>}
object{V_Element(R11,R21,W1,H1)
                 rotate<0,1*90,0>}
object{V_Element(R11,R21,W1,H1)
                 rotate<0,2*90,0>}
object{V_Element(R11,R21,W1,H1)
                 rotate<0,3*90,0>}
translate<0,R1,0>} #end  //--------------- 

//-------------------- testure ----------
#declare Texture1 =
 texture{
   pigment{ color rgb<1,1,1>}
   finish { diffuse 0.9 phong 1}}
#declare Texture2 =
 texture{
   pigment{ color rgb<1,1,1>*0.7}
   finish { diffuse 0.9 phong 1}}
//---------------------------------------
// Base:
box{ <-1,0,-1>,< 1,0.05,1>
      scale <W+0.1,1,W+0.1>
      texture{Texture2}}
//-------- Construction with while loop
// tower:
#declare Nr = 0;    // start
#declare EndNr = 8; // end

union{
#while (Nr < EndNr)
   object{ Element_4(R1, R2, W, H)
           texture{Texture1}
           translate<0,Nr*H,0>}
 #declare Nr = Nr + 1;  // next Nr
#end // --------------- end of loop
object{ Square (R1, W) texture{Texture1}
        translate<0,Nr*H+R1,0>}
translate<0,0.05,0> }
//----------------------------------- end