Stairway lighting

Artistic or photographic credit to Skurk.

This one resonated with me because in my junior year at college 50+ years ago, my term paper for Bio10b was entitled "Visual Adaptations of Deep-Sea Teleosts," an in-depth analysis of retinal adaptations (rod/cone elongation, transmutation, concentration, summation), tapeta, sighting grooves etc etc.  It was the type of paper for which one spends literally hundreds of hours mastering subject matter that will never have even a smidgeon of relevance to one's future career, but that one can still look back at with a measure of satisfaction.

For those interested: more on anglerfish.