diff vs bare: +0/-0
cube([60, 60, 10]);
translate([10, 10, 10]) cube([40, 40, 10]);
translate([20, 20, 20]) cube([20, 20, 10]);
SCAD (3 lines)
cube([60, 60, 10]);
translate([10, 10, 10]) cube([40, 40, 10]);
translate([20, 20, 20]) cube([20, 20, 10]);