"Shaped Note Singing" or
"Sacred Harp Singing" is considered
a folk art form from the Southern U.S. in the 1800s.
The songs are hymns from editions of the Scared Harp song
and are sung loudly and without accompaniment.
Before the first verse, tradition requires that the notes
be sung with
the Fa, Sol, La and Mi note names instead of words.
The music notation in the song books uses different
different notes. Fa is a triangle(flag), Sol is a
La is a square(2 Ls make a square) and Mi is a diamond
(diamonds for me).