First some abbreviations: W1, W2, W3 = Weighing # 1, 2, 3 & Tag balls with characters 'A' through 'L', then
W1 ABC-DEF means: weigh balls A,B,C on left scale and D,E,F on right one. Weighing results: LU = left scale up, LD = left scale down, EQ = equilibrium.
My solution:
(Indentation for next...