Harry Beck famously redesigned the London underground map in 1933.
He was an engineering draughtsman at the London Underground Signals Office, and he realised that – when you’re underground – the map doesn’t have to represent actual geography.
So he redrew it using equal distances between stations joined by vertical, horizontal and 45-degree diagonal lines*. This became the model for underground maps around the world and is still used to this day.
It even inspired me in a 1974 science lesson when studying the relationship between chemical reactions. The teacher told us the diagram in the book was unclear, and set us homework to simplify it.