strap();

module strap(){
        difference(){
                difference(){
                        union(){
                                difference(){
                                        cylinder(h=20,r=14,$fn=100);
                                        cylinder(h=3*20,r=10,center=true,$fn=100);
                                }
                                difference(){
                                        translate([2+1,0,10]){cube([4,50,20],center=true);}
                                        cylinder(h=3*20,r=10,center=true,$fn=100);
                                }
                        }
                        translate([-15+1,0,10]){cube(30,center=true);}
                }
                union(){
                        translate([0,19.5,10]){rotate([0,90,0]){cylinder(h=10,r=3,$fn=100);}}
                        translate([0,-19.5,10]){rotate([0,90,0]){cylinder(h=10,r=3,$fn=100);}}
                }
        }
}