Shape notes - Sacred Harp & Aiken
Create a score in shape notes notation in MuseScore, press a button and the score is converted in 4 shape notes notation or 7 shape notes notation or back to common western notation. This plugin only works with MuseScore 1.3 and MuseScore 2.x. For MuseScore 3, you don't really need a plugin, you can use the builtin feature: Supported notehead schemes
"Shape notes are a music notation designed to facilitate congregational and community singing. The notation, introduced in 1801, became a popular teaching device in American singing schools. Shapes were added to the note heads in written music to help singers find pitches within major and minor scales without the use of more complex information found in key signatures on the staff." (source Wikipedia)
There are two systems of shape notes. The plugin supports both systems.
Seven-shape system or Aiken