Elephants

An elephant is such a wonderful metaphor.

For a system: an Elephant is so big, that it can be difficult understand and grasp the whole picture and get a common understanding.

For teaching methods: some years back, it was believer that the best way to learn, was to write tons of notes and study hard at home. Repeating what you have been taught over and over = memory = elephant.
Now there is an understanding that students have different learning profiles: Some students learn faster with the distraction from music, some requires solitude and silence and others needs to get a practical approach.