Where: Next to the door to the lavatory in the hallway of a midsized apartment in the center of St. Petersburg, off of Sennaya Square. Three families live in the apartment.

Who: Each of the three families has their own light bulb in the lavatory. The wires are connected to meters and each family has their own meter.

This system for lighting the common areas indicates that the light bill is not split among the residents, but rather calculated based on the meter readings. There are also three light bulbs in the hallway as well as in the kitchen.

Turning on someone else's light bulb is a serious transgression which can cause a scene. Frequently the offenders are visitors who may not know which of the switches belongs to their hosts.