Gigantotron
Of course, it can also be used to shrink. Or you'd be stuck at giant-sized!
Explore with this sketch to compare distances, areas and volume between two similar 3-D objects.
The drawings are in modified isometric view and not drawn in perspective, which is why they look a little odd.
One of four similarity stations you can find at: http://mathhombre.blogspot.com/2010/04/similarity-day.html