The despondent professor watched 
her students file out of the classroom. When the last one disappeared 
into the hallway crowd, she turned to the scrawled equations on the 
blackboard, arms crossed.
Big
 O notation, algorithmic complexity. As far as ultimate lessons go, she 
thought, she could’ve done much worse. Her eyes followed the 
mathematical expressions downward to their beautiful conclusions. She 
sighed, wiped the board clean.
Marinne sat down, stooped over her desk, when a gentle knock came on the door frame.