Last Saturday I attended a Westcoast Calligraphy Society workshop with Violet Smythe on Ben Shahn lettering. Shahn was a Lithuanian born American artist best known for his works of social realism. He also did war posters for the United States Office of War Information and worked as a commercial artist.
He developed a unique style of lettering, and Violet and other lettering artists have studied these and now teach them. Below is an exemplar I did during the class. For more samples of Shahn's lettering you can check out Pinterest too.
These letters were all done with a folded pen, shaped like this. Violet said, however, that she didn't actually know what kind of pen Shahn used to make his letters so I'll have fun experimenting with other tools.