group() {
	difference() {
		square(size = [10, 10], center = true);
		circle($fn = 0, $fa = 12, $fs = 2, r = 4);
	}
	multmatrix([[1, 0, 0, 12], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		difference() {
			square(size = [10, 10], center = true);
			multmatrix([[1, 0, 0, 2], [0, 1, 0, 2], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				circle($fn = 0, $fa = 12, $fs = 2, r = 2);
			}
			multmatrix([[1, 0, 0, -2], [0, 1, 0, -2], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				circle($fn = 0, $fa = 12, $fs = 2, r = 2);
			}
		}
	}
	multmatrix([[1, 0, 0, 12], [0, 1, 0, 12], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		difference() {
			square(size = [0, 10], center = true);
			circle($fn = 0, $fa = 12, $fs = 2, r = 4);
		}
	}
	multmatrix([[1, 0, 0, 0], [0, 1, 0, 12], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		difference() {
			group();
			square(size = [10, 10], center = true);
			circle($fn = 0, $fa = 12, $fs = 2, r = 4);
		}
	}
	multmatrix([[1, 0, 0, 24], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		difference() {
			square(size = [10, 10], center = true);
			sphere($fn = 0, $fa = 12, $fs = 2, r = 4);
		}
	}
}