The artist Clinton Lugert of THEY design chose to focus on the film's alternate perspectives as well as the rift in the primary relationship. This lead him to base the Key Art and poster design on the ancient Roman god Janus.

Janus, the two-faced god looks both to the future and the past and therefore presides over: time, transitions, gateways, and the beginning and ending of conflict. 

In the film, Emily is an author who controls her own perspective on reality, which gives her a god-like quality. While John is dealing with beginnings and endings within himself. This visual is then paired with an intersecting Venn diagram to create a graphically simple, but successful visual statement.