Artist Kyle McDonald has done a lot of pieces that play with how technology can track and connect people in ways that they might never realize. Sometimes, these are meant to be unsettling: Conversnitch put secret microphones in public places and transcribed the conversations they captured to Twitter, and People Staring at Computers brought him scrutiny from the Secret Service. But others are serendipitous and delightful: working for Spotify, he created a map (which is in fact known as Serendipity) where visitors can see when any two users start playing the same song at the exact same time.

In 2013, McDonald was commissioned to create an art installation in Korea. His project, Sharing Faces, placed mirror-like screens in the Korean city of Anyang and in Yamaguchi, Japan. When a visitor looked into it, they would see someone else's face — placed and posed like their own. When they moved, the screen would cycle through images and find one matching the new pose, creating the impression of a morphing person following your every move. The images came from other visitors to the installations, whose pictures were captured while they stared at the images. Every time you watched other people match the way you moved, you were creating material for some future visitor to see.

The technical details of its face capture and tracking are on Github, and they help illuminate the project a bit. Conceptually, though, it's a neat and elegant idea, a mirror that shows you other people's faces — McDonald suggested the collaboration with Japanese artists because of the ongoing cultural and political tension between the two countries. The installation has since come down, but the video above gives you an idea of what it's like to