difference(){
 union(){
  minkowski(){
   difference(){
    translate([0,0,5])
     cylinder(h=15.5, d=14);
    union()
     for(i=[360/9:360/9:360])
      rotate([0,0,i])
       translate([7,0,-1])
        cylinder(h=22, d=5);
   }
   sphere(1.5);
  }
  cylinder(h=6, d=20);
  translate([0,0,6])
   cylinder(h=5, d1=20, d2=10);
 }
 union(){
  cylinder(h=6, d=16);
  translate([0,0,6])
   cylinder(h=1, d1=8, d2=6);
  cylinder(h=20, d=6);
  translate([0,0,20])
   cylinder(h=1, d1=6, d2=0);
  translate([0,-2.75,9])
   cube(5.5);
  translate([0,0,11.75])
   rotate([0,90,0])
    cylinder(h=10, d=3);
 }
}