$fn=100;
border=1;

difference() {
    minkowski(){
        cube([21,11,11]);
        rotate([90,0,90]) cylinder(h=1,r=border);
        cylinder(h=1,r=border);
    }
    translate([9,6,-2]) cylinder(h=16, d=7,center=false);
    translate([5,2.5,-2]) cube([4,7,16]);
    
    translate([18,6,6]) rotate([ 80,0,0]) cylinder(h=20, d=5,center=true);
    translate([18,6,6]) rotate([ 85,0,0]) cylinder(h=20, d=5,center=true);
    translate([18,6,6]) rotate([ 90,0,0]) cylinder(h=20, d=5,center=true);
    translate([18,6,6]) rotate([ 95,0,0]) cylinder(h=20, d=5,center=true);
    translate([18,6,6]) rotate([100,0,0]) cylinder(h=20, d=5,center=true);

    translate([2,1.5, 0]) cube([2.5,9,14]);

    translate([1,6,6]) rotate([ 0,90,0]) cylinder(h=10, d=5,center=true);
}