One of the kids I help after school showed me this drawing that his teacher showed him. After seeing him draw it in front of me, I know I will never forget the relationship between Gallons, Quarts, Pints, and Cups ever again.
There was something powerful about watching him draw the picture for me, which is why I have the video, and not just an image.
When I googled it, there are a few good image hits (so it must be a common thing). I just had never seen it.