More Grocery Shrinking Options

There has to be a volume problem/project in here. The setup: you work for some company that wants to cut costs by shrinking its product... but you don't want the consumer to know. Consider 3 options for shrinking the product without making it too different:

• Change the shape of the packaging (box 1 in the comic above). Needs to be a change that's subtle enough that someone won't notice. Could be totally dramatic (changing rectangular package to a cylinder or frustrum). Could be subtle (shave a little bit off here, a little bit off here, no one will notice). Could be sneaky (when bottle manufacturers make the bottom of the bottle not flat).
• Make the actual product smaller (upper right box in the comic above). Seriously, how much could you save by making the holes in cheerios or bagels bigger? 
• Filling the package with something else (the ice cream gnome above). Less ice cream, more toys!

I wonder what givens you'd need to give kids to start with and how open-ended it actually could/should be. I would love for kids to actually build their packages so that they could show why it's a sneaky change!

(Yes, this is teaching kids to be corporate scammers, but hey, preparation for the real world, right? Maybe it will also teach them to be suspicious of corporate scammers!)