Shaped Note Singers
Shape-Note Singing,
a musical practice and tradition of social singing from music books printed in shape notes. Shape notes are a variant system of Western musical notation whereby the note heads are printed in distinct shapes to indicate their scale degree and solmization syllable (fa, sol, la, etc.).
Image Credit: By Baptist Harmony (?) - http://www.ccel.org/ccel/walker/harmony/Page_16.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=1539610