It takes a very long time to create a concise layout of a public transit map.
To make things easier to understand the obvious decision is to use symbolic geography in lieu of real maps so that everything fits in a legible manner. Over at the subreddit r/DataIsBeautiful, Reddit user vinnivinnivinni had thew idea to create an animated comparison of a Berlin subway map compared to its real geography.
The post went viral and several other users chimed in with their own contributions. Gathered here are some of the best examples, but you can see a few more on Twisted Sifter .