Compare each adjacent pair, with the highest values bubbling to the top.
Detailed Instructions
Split the boxes into 2 equal piles (of 3 boxes).
Now split each pile into 2 piles (of 1 or 2 boxes).
For each pile, compare the 2 boxes and put them in order (lightest first).
Compare the lightest boxes from pile 1 and pile 2. Put that to one side.
Repeat until you have merged the two piles fully.
Repeat step 3 for piles 3 and 4.
You should be back to 2 piles of 3 boxes. Repeat step 3 to merge these 2 piles.
And finally, once you've completed the exercise, try to work out the maximum number of comparisons you would need to solve the problem with different numbers of boxes.
