How to have a conversation across time and space

(But it's going to be a frustrating one.)

In the 2006 science fiction romantic comedy The Lake House, Sandra Bullock stars as someone who’s able to mysteriously communicate through time with a previous resident of her house (played by Keanu Reeves) through a magic mailbox. Bullock’s character, a lovelorn doctor, places letters inside the mailbox in 2006, and Reeves’ character—an architect, beca…