Even though I'd arrived atypically early, now I was running late, and I still needed to grab blank transparencies and another Sharpie from the department office. (By now you've probably guessed that there are no chalkboards or whiteboards in this room.) So that students wouldn't think class was cancelled, I projected onto the screen a note to the effect of "Today: 4th Law of Hamster Thermodynamics," scrawled on a piece of cellophane sandwich wrapper, and ran upstairs.
I returned to find most of the students seated and talking to each other but nary a (text- or note-) book open on a desk. I sighed, flipped a transparency onto the projector, and started to write.
"Uh, professor?" came a confident voice from the student seated two desks behind the projector.
"Yes, Mr. Hruutspungar."
"Could you, like, move the projector? It's blocking the screen and we can't see around it."
It is the academic's nature to consider new evidence; if there's one thing we know, it's that we hardly ever know everything about anything. I looked back at the projector, then surveyed the room. The aggrieved student's desk was surrounded by several unoccupied desks; I hypothesized that other students had chosen theirs for the clear view they afforded. It was easy to test this by estimating sightlines from the corners of the screen to the observers' eyes. Additionally, I was more than a little familiar with this room---I've logged many hours in it and have occupied every desk myself during seminars etc. over the past decade. In about the time the average person takes to read the first sentence of this paragraph, I concluded that the projector was not significantly obstructing anyone's view but Hruutspungar's.
Yet... I wanted more data. "When you say 'we can't see around the projector,' you mean just yourself, right?"
"No, I mean everybody."
I exchanged quizzical looks with Hruutspungar's nearest classmate and turned to another, my expression imploring clarification. I was met with upturned palms and a shrug, the international sign of I have no idea what the fuck this guy's talking about.
I was suddenly reminded of the three mountain problem, and it just escaped:
"Didn't Piaget figure all this out with a bunch of three-year-olds?"
And did a flash of recognition cross the faces of a few students? I savored the illusion that it did. Ah, but not dear, blankly uncomprehending Hruutspungar's. Even so, I regretted my implied unfavorable comparison and tried to make amends.
"I'm sorry. That last thing... it's from another problem I've been working on. Please ignore it." I shifted to a croon and gestured to another desk. "Mr. Hruutspungar, I believe you'll find the view from this desk far superior to that of your own."
"No, you need to move the projector. The top part is sticking up and..."
"The projector stays. Let's try my idea."
"But I don't see how that's..."
"That's rather the point, yes? To see?" I took a second to temper my rising snark. "Please, just... switch desks."
Hruutspungar grudgingly dragged his backpack to the other desk and schlumpfed into the seat, his expression brightening as he again fixed his gaze to the screen.
"Hey, did you move the projector?"
"Well, it's like in a totally different position now, so you musta." He pronounced it as he writes it.
I was lost for words, but one student was not.
"Actually, Spung, maybe you thought you were moving from here to there, but what really happened is, the projector and everything else in the room moved in an equal and opposite direction."
Other students took up the chain: "Not just all the stuff, but the room itself." "The whole building!" "The continent" "The planet!" "The universe!" Some raised their hands to their heads and then splayed fingers and mimicked explosions: minds blown.
I was at once amazed, gratified, hopeful, resigned, despondent. I had no where to put it all.