module base() { offset(5, $fn=32) square([24, 45], center=true); };

difference() {
    union() {
        linear_extrude(1) base();
        translate([0, 0, 0.9999]) minkowski() {
            linear_extrude(0.001) offset(-5) base();
            cylinder(3, 5, 0, $fn=32);
        }
    }
    
    for (i=[0,-1,1,-2,2]) {
        translate([0, i*8, 0.7]) {
            translate([-20, -2, 0]) {
                cube ([40, 4, 1.5]);
            }
            
            translate([24/2, -2, 0]) {
                cube ([40, 4, 10]);
            }
            
            translate([-24/2-40, -2, 0]) {
                cube ([40, 4, 10]);
            }
        }
    }
    
    translate([0, 11, 5+0.7]) cube([24-10, 14, 10], center=true);
    translate([0, -11, 5+0.7]) cube([24-10, 14, 10], center=true);
}