As part of his design studies, Zac Ong created a form of wearable art which contains various sensors to detect level of intrustion with regards to the wearer's personal space. From a mild glow, to bright LEDs... and finally a rotating laser beam - for example:
An interesting synergy of Arduino, electronics and avant-garde fashion. Nothing would shake up a peak-hour train ride more than wearing one of these. If working on these systems, please take care not to look directly at laser beams or give others the opportunity to do so.