Writing in Dual Dialogue uses the caret (^) to signal when a line should pair up with the line that comes before it.
For example, this section of Greta Gerwig’s script for Little Women looks like this on the page:
And would look like this in Highland 2:
LAURIE
AMY! You’re so /grown up!
AMY^
/You wrote you’d come to the hotel!
LAURIE
I looked for you and couldn’t find /you anywhere!
AMY^
/You didn’t look hard enough!
LAURIE
Maybe I just didn’t recognize you, you’ve become so beaut/iful.
AMY^
(making a face)
/Please don’t.