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);}}}}}