The Guardian – Alex Bellos
“Today’s puzzles all concern cubes of cheese. You’ll need to be as sharp as a cocktail stick to skewer them. 1. You have a cube of cheese that measures 3 x 3 x 3 inches, and you want to slice it into 27 smaller 1 x 1 x 1 inch cubes, as shown below. If you have a straight knife, what’s the minimum number of slices you need to do it? You are allowed to rearrange the pieces after each slice.” (more)