A small observation, but when Q said "Think Mirror", Mirror is capitalized. Like it is a title or something.

I did find a 1975 movie called Mirror (The Mirror in the US), that seems to be told in a non-linear way. Besides that I haven't found much. Posting incase other Anons can think of anything.

Map Key or Legend. A map key or legend is included with a map to unlock it. It gives you the information needed for the map to make sense. Maps often use symbols or colors to represent things, and the map key explains what they mean.

http:// historymatters.gmu.edu/mse/maps/what.html

"So what is a map? A map is text. John Pickles, a geographer with interests in social power and maps, suggests:

maps have the character of being textual in that they have words associated with them, that they employ a system of symbols within their own syntax, that they function as a form of writing (inscription), and that they are discursively embedded within broader contexts of social action and power.

In this view, maps are a form of symbolization, governed by a set of conventions, that aim to communicate a sense of place. To fully understand a map we need to know how to decode its message and place it within its proper spatial, chronological, and cultural contexts. Maps, even modern maps, are historic. They represent a particular place at a particular point in time. This definition of a map (although, like the mirror image idea, is also problematic) suggests that maps can afford the viewer a great opportunity to gain insights into the nature of places."