Is there an existing icon that is recognized as a request / suggestion that a user rotate their mobile device?
I am converting an OLD website to be more mobile friendly. (responsive) I have existing forms that already fit decently if viewed in landscape mode, (My test device is relatively small, the Samsung Galaxy Avant) so one option might be to give them alternate content asking them to rotate their device for a better view.
I'm not sure if a tilting rectangle or rotational arrows (or combination of the two) is better. (Along with, not instead of, English text)