::NORTH VERSUS SOUTH::
Last night, as I walked away from the museum at about 8:30 PM, I crafted a geometry lesson from the sky. My eyes were immediately drawn to strange bright yellow light. To my north, the low-slung stratus clouds glowed with the sunset's warmth. Their lines, in their fuzzy, zero-slope flatness, made me think, "y=6, y=7, y=9, y=10, y=13." See?

Condensation meets function.
Then, walking to my car, I spied the moon in the southern sky, peeking at me from behind some gauzy cirrus, and I thought, "(-12, 32)." See again?

Single solution.