I have twelve boxes and a simple scale, the old fashioned ones that tell if one side is heavier than the other, or if the two weights are equal. One of the twelve boxes is either heavier or lighter than all the rest. I can only use the scale three times.

All the boxes are completely identical, and I can only find which one is heavier or lighter by weighing. I can't put just one box against another, because then one could be lighter than the rest, or the other could be heavier than the rest, or they could weigh the same.

I have three tries on the scale. I cannot start over after eliminating some. I have to use a way to find which one is lighter or is heavier than the rest on the first try.

What one is a different weight, and is it lighter, or is it heavier?