My mother introduced an interesting question... she wanted to compare todays global economy with the roman empire. I am not in any position to theorize since I have only very very limited information on both subjects, but I thought this would potentially be a good question for Ben and Victoria.
Also, I feel like I just discovered how to use the internet for myself. This is so... cool.
http://www.nedkahn.com/sand.html# Magnetic Field Stone - Exploratorium, San Francisco, California. 1996
Inspired by traditional Japanese basin stones, this artwork uses a rotating magnet to sculpt natural magnetite sand into ever-changing spiral patterns. Viewers can run their hands through the sand and alter the pattern. The artwork was a collaboration with stone mason, Edwin Hamilton.