or three pencil erasers are
placed on the floor in the aisle on one side of the room at the side of
each desk in that row.
At a signal, the pupils in those desks pick up one eraser and pass it to the person who sits across the aisle.
They do the same with the other eraser, passing them along until finally all the erasers are on the floor of the aisle on the other side of the room.
Then they pass them back, one by one, untill all erasers are back in their original positions.
The row having the erasers back first win a new eraser!..and you get to quiet the troups!