Twin Mirror
Improv Everywhere, is the group that brought you such stunts as a bunch of people freezing in place at Grand Central Station, creating a time loop in a Starbucks, and my personal favorite: getting 80 folks to dress up in Best Buy employee outfits and swarm a Best Buy. Their most recent mission was getting identically dressed identical twins to fill a subway car, symmetrically. I knew twins were good for something.
Human Mirror - Improv Everywhere
Note to self: All sets of identical twins seem to own matching pairs of clothes. How sneaky...