module tower (coord) {
	translate(coord) {
		rotate([0, 0, (360/8)/2]) {
			cylinder(11, 2.5, 2.5, $fn=8);
			translate([0, 0, 10])
				cylinder(2, 3, 3, $fn=8);
		}
	}
}

// towers blue
difference () {
	tower([0, 0, 0]);

	//walls are red
		translate ([0, -1, -1]) 
			cube([20, 2, 8.5]);
		translate ([-1, 0, -1]) 
			cube([2, 20, 8.5]);
}