a = 1;
b = 2;
c = 3;
echo(a, b, c);
let(a = 5, b = (a + 8), c = (a + b)) {
	echo(a, b, c);
	difference() {
		cube([a, b, c], center = true);
		let(b = (2 * a), c = (b * 2)) {
			echo(a, b, c);
			rotate([0, 90, 0]) cylinder(d = b, h = c, center = true);
		}
	}
}
