/* CONFIG PART */

desk_thickness = 8;
moulding_size = 10;
thickness = 5;
rounding = 2;

$fn = 30;

/* END OF CONFIG PART */

top_width = moulding_size + thickness * 2;
bottom_width = top_width + desk_thickness * 2;
top_depth = moulding_size + thickness; 
bottom_depth = moulding_size;
full_depth = top_depth + bottom_depth;

module rounded_square(width, height, rounded = true) {
    if (!rounded) {
        square([width, height], center = true);
    } else {
        hull() {
            move_x = width / 2 - rounding;
            move_y = height / 2 - rounding;

            translate([move_x, move_y]) circle(r = rounding);
            translate([-move_x, move_y]) circle(r = rounding);
            translate([move_x, -move_y]) circle(r = rounding);
            translate([-move_x, -move_y]) circle(r = rounding);
        }
    }
}

module base() {
    translate([0, -full_depth / 2]) hull() {
        translate([0, top_depth / 2 + bottom_depth]) {
            rounded_square(top_width, top_depth);
        }

        translate([0, bottom_depth / 2]) {
            rounded_square(bottom_width, bottom_depth);
        }
    }
}

module without_moulding() {
    difference() {
        base();

        translate([0, full_depth / 2 - moulding_size / 2]) {
            rounded_square(moulding_size, moulding_size, false);
        }
    }
}

without_moulding();