All pieces with formal organization can be seen as expanded or modified versions of the basic paradigms below.
- Strophic - one section repeats over and over again: AAA etc.
- Binary - two contrasting sections: AB
- sections may be repeated, resulting in AABB
- Ternary - two contrasting sections, the first section returns: ABA
- sections may be repeated, resulting in AABBAA or AABBA
- this form is distinct from binary form because the A section returns after the B section
- Rondo - one section returns over and over again (a refrain), alternating with contrasting sections
- there are several different versions of rondo form (ABACA, ABACABA, etc.), but it is always defined by many returns of the A section separated by contrasting material
- Theme and Variations - same material returns but is slightly or substantially varied from its original form: AA1A2A3 etc.
- variations are indicated with superscript numbers
Add-Ons: Introduction and Coda
There are two optional sections that can be added onto any form: an introduction at the beginning, and a coda at the end. An introduction is designed to grab the attention of listeners and 'set the stage' for the body of the piece. A coda (from the Italian word for 'tail') is designed to bring a greater sense of closure to a piece than would be possible within the body of the form.
Adding an introduction and/or coda to a piece does not change its fundamental form - these sections are considered ancillary and simply provide a frame for the main substance of the piece.
Sometimes a large work, like a symphony, consists of several distinct movements or smaller pieces that are related but distinct from each other. These large works are called composite forms. Each movement of a composite form may be ternary, binary, or any form, but it is seen as belonging to a larger meta-form. This is similar to the idea of a concept album in popular music. Each piece is distinct from the others, but the collection is conceived as a whole.
Examples of composite forms include symphonies (usually 4 movements), concertos (3 movements), song cycles (groups of several songs telling a story or sharing a theme), and suites (collections of stylized dance movements).
It is important to note that there are some pieces that do not fit into any of the forms discussed above. This occurs when pieces lack formal repetition and variation, and do not divide into two contrasting sections as in binary form. These pieces do not follow a fixed form, but are through-composed, meaning that the composer created new material for each section of the piece. Many examples of this can be found in Renaissance madrigals and Romantic art songs (Franz Schubert's Lieder, for example), but there are a few through-composed pieces in popular music as well. These include Queen's "Bohemian Rhapsody", The Beatles' "Happiness is a Warm Gun", and Radiohead's "Paranoid Android".