Thanks Jack for this riddle
We have 12 billard balls (numbered from 1 to 12) and a pair of scales.
One of these balls is havier or lighter than the other balls! But we don't know if it's heavier or lighter...
We want to find which ball have a different weight and it's heavier or lighter.
How can we do that with maximum 3 weighings?
Congratulations Le Pougnezu on his solution of the 04/07/06 but don't look at it, it's always better to find oneself...
If you want to see the (false) solutions which were sent to me.