And here, I'll prove it, I went back and took some photos. Now, these aren't great-quality renditions for several reasons -- a) I'm sure they look much better inside their offices, the intended wallpaper orientation broadcasting inward rather than projecting outward b) I'm sure the sun has bleached the colour out of the Post-it Notes, c) supposing that the colours available in Post-it form were remotely close to the original palettes to begin with. And of course, d) you have the caveat that the office-pointing creations were mainly done for the benefit of their creators, meaning that what we see for the most part are mirror-images of the sprites. But all the same, it's a great curio distributed across several offices in several buildings! I've sorted them chronologically by game, and included original sprite art where possible for purposes of comparison.
The courtyard behind the Beaty Biodiversity Museum is punctuated by 8-bit video game pixel art made of Post-it Notes in office windows— Rowan Lipkovits (@UnwashedMass) December 30, 2016
So it's a growing phenomenon!
@UnwashedMass My roommate used to work/research in the building, but I only remember there being 1 or 2 post-it-windows at that time.— Quite Likeable (@chanson_dada) December 30, 2016
Bonus! A reader noted that she had witnessed similar office-window pixelart near her workplace and submitted the following (historical, sadly -- it's been since removed) Smash-Bros. mash-up taste of Link, a Boo Buddy, and his phantasmal colleague from Pac-Man: