Human Mirror.

Improv Everywhere, is a group based in New York City which is well known for their urban pranks creating scenes of joy and surprise in public places. And here we have 'Human Mirror' one of their 80 achievements, where a subway car was filled with identical twins, creating a human mirror.
The twins were instructed to do everything they could to look identical. And they did an awesome job from their attire to matching accessories.
The twins sat on either side of the car, directly across from their sibling and each set of twins would mirror the actions of the other (as closely as possible) e.g. if one scratches his head, the other had to do the same and if anyone asked what was going on, they were to claim to not notice anything unusual.
Complete details, more photos and video are available at official website.

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