"I wish," said Jon, "that I'm big because I have the power to grow and shrink any part of my body by a factor of three, and I'm this way because I'm using the power now, not because I'm permanently big."
Jon concentrated and found himself able to shrink again. If he just shrank, he shrank in proportion, which didn't work since he was 18 inches taller but 3 times the weight; but by changing parts of himself, he was able to return to normal.
The wish, of course, was triplicated like all other wishes, so he gained the power to become 9 times as big or small instead of 3. But Jon didn't notice that his power was more useful than he had asked for.
As far as he was concerned, the wish just worked. But he was still puzzled about why the first wish didn't work. Deciding to make a harmless wish to try it out, he wished....
