module example002()
{
	intersection() {
		difference() {
			union() {
				cube([30 30 30], center = true);
				translate([0 0 -25])
					cube([15 15 50], center = true);
			}
			union() {
				cube([50 10 10], center = true);
				cube([10 50 10], center = true);
				cube([10 10 50], center = true);
			}
		}
		translate([0 0 5])
			cylinder(h = 50, r1 = 20, r2 = 5, center = true);
	}
}

example002();