Repetitive tunings are alternative tunings for the guitar. A repetitive tuning begins with a list of notes that is duplicated, either at unison or at higher octaves.Among regular tunings, there are four repetitive-tunings (besides trivially repetitive tunings such as C-C-C-C-C-C); this article discusses three minor-thirds tuning, major-thirds tuning, and augmented-fourths tuning (but not major seconds tuning, which is not repetitive on six strings).