In **continuous binary form**, the first reprise instead closes in a secondary key. In the diagrams below, the superscripts 1 and 2 indicate tonic and non-tonic keys, respectively. $ \text{||: A}^{1\to2}\text{ :||: B}^{2\to1}\text{ :||}\quad\text{or}\quad\text{||: a}^{1\to2}\text{ :||: b}^{2}\text{ a}^{\prime 1}\text{ :||} $