Why would Iwai rig a real (more specifically, mechanical) piano to accept computer-generated visual input in order to make sounds when an entirely digital system would have sufficed? Or why not allow visitors to access and play the piano directly? I think this gesture highlights the tension that many people would have felt in the mid-1990s when digital interfaces were far less common than they are today. Perhaps Iwai was suggesting that the interfaces of the time were so illogical and unintuitive that they could never replace the physical ones with which most people were familiar. By placing the primary interface of the piano—its keys—just out of reach, Iwai forces visitors to use a surrogate interface in order to play it. The interface, and with it, the entire notion of interactivity, is exposed when the physical distance between visitor and piano becomes so great that the visitor is forced to consider how the system interprets their (inter)action.