Robert Gligorov, built this magical musical birdcage installation made up of two pianos placed back to back with a glass enclosure on top for canaries to live and play. As they fly from perch to perch, their weight moves the rods that tickle the ivory, creating a harmonies to their songbird melodies.
Wouldn't you love to hear a recording of their music? :)
{Images via Ridiculously Interesting}