As one class at Miami Ad School Brooklyn spent Tuesday night spray-chalking a memorial to the victims of 9/11 in Queens, another class was creating a street art project of their own. Six international students from the school are behind a guerilla project that turned pedestrian traffic lights around Manhattan and Brooklyn into symbols of remembrance. The stop symbol was modified to resemble the fallen Twin Towers, while a message reads "9/11. Forward. Together." underneath it.