Stressfree

1   weight 6 ping pongs with another 6 ping pongs. see which side is heavier
4 n8 \" `- B4 @$ |. g1 z公仔箱論壇2   spilt the heavier side ping pongs in half and weight against each othertvb now,tvbnow,bttvb7 C' n* O( T2 N6 x* H* H% ^
3   weiht either ping pongs one on one then you will know which is the heavy one.