rotate_extrude(){
    difference(){
        union(){
            translate([10.5,0,0]) square([5,7], center = true);
            translate([19.5,0,0]) square([5,7], center = true);
        }
        translate([14.75,0,0]) circle(3.5);
    }
}

for (ball=[0:30:360]) {
    rotate([0,0,ball])
    translate([14.75,0,0])
    sphere(r=3.25);
}