12 balls names A B C D E F G H I J K L
$ I4 t- |2 J# F. j* U. _- A# a1St A B C D : E F G H if balance 5 l3 y' M. m( P1 L" x8 \ c: X
2nd A B (or either 2 of A-H) : I J if again balance if A B > I J (implies the different is light ball is I or J)+ G% I4 G" n& S4 p, ?
3rd A (or either A-J) : K if again balance 3rd I : J (the lighter is different). k! k: n4 |7 G0 h- P, v- v0 n2 _
L is different |