>I have Opinions Good. Then fork the library and modify it to your liking, optionally republish. >one box is fully within the other, and centered This implie

>I have Opinions Good. Then fork the library and modify it to your liking, optionally republish. >one box is fully within the other, and centered This implies containment/stacking and wouldn't require an arrow. However, you could do worse than drawing 4 arrows from the edges of the surrounding rectangle.