# Who came up with the box and arrow diagrams for electron configurations?

In general chemistry texts, the electron configurations are sometimes shown in boxes with up and down arrows to show the concept of paired spins. My impression for years was that Hund used such diagrams. However, flipping through his book Linienspektren und Periodisches System der Elemente which used the s,p, d, f notation in a modern way, there is no such use of box diagrams with up and down arrows. Does anyone know who introduced this so-called box notation? Thanks.