the thing that bugs me about that is that its using volume to illustrate a fact about area. Now of course it's legitimate assuming all the rectangular prisms have the same depth but it still feels a bit like some sleight of hand is taking place.
> Now of course it's legitimate assuming all the rectangular prisms have the same depth
But I still consider it to add an extra element to the demonstration that may potentially confuse people who look at it (or have them wondering 'are they all the same depth or not?'), which is something you don't want in an educational demo.
