In France, a lot of guitar/bass (pop/jazz) musicians use a graphical way of representing a songs chord progression. It is called the "grid" ( translation of "grille"?) of a song.
It looks like this (source):
Edit: Each square stands for a bar (usually 4 beats but can also be 3 beats), with the chord you are supposed to play inside it (second line, first square: Dm7). When a square is split in two (say, first line, first bar), it means you have 2 beats on Am, and 2 beats on Bdim.
It is useful in the sense that it gives in a concise way the chord progression, bar by bar, for musicians that don't need/want the melody. A french-language Wikipedia page describes this.
Questions: is this type of notation used elsewhere in the world? How do you (would you) call it?
As you can see, the linked english-language wikipedia page is quite different.
I have checked also on Wikipedia's musical notation page, this notation does not seem to be mentioned. Before editing that page, I would like to have some feedback from others.