ABSTRACT
Binary and ternary period forms are largely defined in varying degrees by Statement/Contrast and Statement/Contrast/Return. There are two types of binary design in music: Binary and rounded binary. Binary form is a two-part form in which each part is proportionally equivalent, with contrasting material in the second part. The form is symbolized by the letters A-B. Rounded binary is also a two-part form but the contrasting material in the second part does not stand on its own proportionally and harmonically. In order to match the length of the first part, the second part needs a partial return of the first part. The form is symbolized by the letters A-B/A’'. Ternary is a form where there are three distinct sections usually consisting of a statement, contrast, and restatement. All three sections stand on their own proportionally and harmonically. The form is symbolized by the letters A-B-A.
