group() {
	circle($fn = 0, $fa = 12, $fs = 1, r = 5);
	multmatrix([[1, 0, 0, 15], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		square(size = [10, 10], center = true);
	}
	multmatrix([[1, 0, 0, 30], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		polygon(points = [[-5, -5], [5, -5], [0, 5]], paths = [[0, 1, 2]], convexity = 1);
	}
	multmatrix([[1, 0, 0, 0], [0, 1, 0, -15], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		difference() {
			circle($fn = 0, $fa = 12, $fs = 1, r = 5);
			multmatrix([[1, 0, 0, 0], [0, 1, 0, -6], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				square(size = [12, 12], center = true);
			}
		}
	}
}