group() {
	rotate_extrude(convexity = 1, $fn = 0, $fa = 12, $fs = 2);
	rotate_extrude(convexity = 1, $fn = 0, $fa = 12, $fs = 2);
	rotate_extrude(convexity = 1, $fn = 0, $fa = 12, $fs = 2) {
		cube(size = [1, 1, 1], center = false);
	}
	rotate_extrude(convexity = 1, $fn = 0, $fa = 12, $fs = 2) {
		multmatrix([[1, 0, 0, 20], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
			circle($fn = 0, $fa = 12, $fs = 2, r = 10);
		}
	}
	multmatrix([[1, 0, 0, 50], [0, 1, 0, -20], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		difference() {
			rotate_extrude(convexity = 1, $fn = 0, $fa = 12, $fs = 2) {
				multmatrix([[1, 0, 0, 20], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
					difference() {
						circle($fn = 0, $fa = 12, $fs = 2, r = 10);
						circle($fn = 0, $fa = 12, $fs = 2, r = 8);
					}
				}
			}
			multmatrix([[1, 0, 0, -50], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				cube(size = [100, 100, 100], center = true);
			}
		}
	}
	multmatrix([[1, 0, 0, 50], [0, 1, 0, 50], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		difference() {
			difference() {
				rotate_extrude(convexity = 1, $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 20], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						circle($fn = 0, $fa = 12, $fs = 2, r = 10);
					}
				}
				rotate_extrude(convexity = 1, $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 20], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						circle($fn = 0, $fa = 12, $fs = 2, r = 8);
					}
				}
			}
			multmatrix([[1, 0, 0, -50], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				cube(size = [100, 100, 100], center = true);
			}
		}
	}
	multmatrix([[1, 0, 0, 0], [0, 1, 0, -60], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		rotate_extrude(convexity = 1, $fn = 1, $fa = 12, $fs = 2) {
			multmatrix([[1, 0, 0, 20], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				circle($fn = 1, $fa = 12, $fs = 2, r = 10);
			}
		}
	}
	multmatrix([[1, 0, 0, 0], [0, 1, 0, 60], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		rotate_extrude(convexity = 1, $fn = 0, $fa = 12, $fs = 2) {
			multmatrix([[1, 0, 0, -20], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				square(size = [10, 10], center = false);
			}
		}
	}
}