carpet.gif author=PhET notes=Noah P. on 4-27-2009
concrete.gif author=PhET notes=Noah P. on 4-27-2009
ice.gif author=PhET notes=Noah P. on 4-27-2009
house.gif author=PhET notes=Noah P. on 4-27-2009
door.gif author=PhET notes=Noah P. on 4-27-2009
door-background.gif author=PhET notes=Sam Reid
robot.gif author=PhET notes=Noah P. on 4-27-2009
truck.gif author=PhET notes=Noah P. on 4-27-2009
truck_top.gif author=PhET notes=Noah P. on 4-27-2009
truck_top_back.gif author=PhET notes=Noah P. on 4-27-2009
truck_top_front.gif author=PhET notes=Noah P. on 4-27-2009
truck_wheels.gif author=PhET notes=Noah P. on 4-27-2009
empty-key.png source = Microsoft Clip Art
