The weekly post on the Arduino Micro,  made in collaboration with Adafruit, is dedicated to an installation for kids made by Scott Garner, a designer, developer and craftsman:

Reach is a large-scale interactive mural and musical instrument created for the Children’s Museum of Pittsburgh as part of the Tough Art residency program. There are no visible electronics, but when users touch both the moon and a star (either alone or by holding hands with others) a tone is played.

The Arduino sketch and PureData patch are viewable on GitHub and below you can watch an inspiring video of the “Making of”: