To add to Macbeth’s growing theme of darkness, his castle should be dark. Dark in the color, not so much that it looks like an evil lord lives there. There should be one tower, where Macbeth sleeps because he wants to be above Duncan and anyone else that stays with him. As far as what surrounds the castle it should be forest, not mountains. A forest represents how people can get lost while trying to get to, or understand him. A mountain range would suggest that it is impossible to reach him, which is not the case.