// unit: mm
base1 = [45, 5, 20];
base2 = [
    base1[0],
    20,
    5
];
DMU_hole_separation = 37;
screw_diameter = 3.2;
screw_margin = 0.05;

union() {
    difference() {
        cube(base2);
        translate([base2[0]/2,base2[1] * 0.7,base2[2]/2]) 
            cylinder(h = base2[2], d = screw_diameter + screw_margin, center = true, $fn = 360);
    }
    translate([0,0,base2[2]]) difference() {
        cube(base1);
        translate(base1/2) {
            rotate([90,0,0]) translate([-1 * DMU_hole_separation/2,0,0])
                cylinder(h = base1[1], d = screw_diameter + screw_margin, center = true, $fn = 360);
            rotate([90,0,0]) translate([DMU_hole_separation/2,0,0])
                cylinder(h = base1[1], d = screw_diameter + screw_margin, center = true, $fn = 360);
        }
    }
}