Stressfree

1   weight 6 ping pongs with another 6 ping pongs. see which side is heavier
8 ^. o" D4 H% J: g* u) R9 T) H. D公仔箱論壇2   spilt the heavier side ping pongs in half and weight against each other
# n1 z5 c4 Y& U+ u% e5.39.217.773   weiht either ping pongs one on one then you will know which is the heavy one.