group() {
		intersection() {
			difference() {
				union() {
					cube(size = [30, 30, 30], center = true);
					multmatrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, -25], [0, 0, 0, 1]]) {
						cube(size = [15, 15, 50], center = true);
					}
				}
				union() {
					cube(size = [50, 10, 10], center = true);
					cube(size = [10, 50, 10], center = true);
					cube(size = [10, 10, 50], center = true);
				}
			}
			multmatrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 5], [0, 0, 0, 1]]) {
				cylinder($fn = 0, $fa = 12, $fs = 2, h = 50, r1 = 20, r2 = 5, center = true);
			}
		}
	}