Rounded Binary Form Theory Things   William Wieland
Continuous or Open Rounded Binary
Example: Mozart Tema (Andante) from Piano Sonata in D major K. 284
Like binary, rounded binary is often a continuous or open form meaning the two principle sections modulate. However, the first section may cadence on tonic.

Like ternary, rounded binary features a recapitulation of the opening material. Unlike ternary, the restatement is usually partial and the contrasting section B is not as substantial.

Rounded binary is a precursor of sonata form.
See also Song Form