square();
translate([2,0,0]) square([1,1], true);
translate([4,0,0]) square(size=[1,1], center=true);
translate([6,0,0]) square([0,0], true);
translate([0,2,0]) square([1,0], true);
translate([2,2,0]) square([0,1], true);
translate([4,2,0]) square([1,2], true);
translate([6,2,0]) square([2,1], true);