"QR tracks" is an interactive sound art piece that weaves together the sounds of the city and the audience's participation. When the QR codes on the wall are read with a smartphone, the sounds that the artist recorded in the field in the city are played, and a soundscape is generated in real time depending on the number of visitors, the combination of selected codes, and the timing of playback. The movement of the audience creates a three-dimensional acoustic space, creating a one-of-a-kind musical experience. As the chaotic sounds of the city come together, each individual interpretation forms an image of the city, raising awareness of the connection as a community and attachment to the place. This work can be deployed in any city, and will depict different sonic expressions in each city in which it is exhibited.