These three mysterious letters appear at certain moments throughout the text, 180 times in all. No one has ever adequately explained them, though every reader feels their effect.
-- The Norton Anthology of World Masterpieces, Fifth Continental Edition (1987)
This CSS file, when applied to your browser while visiting twitter.com, occasionally appends the trigram AOI (rendered in stylish small-caps) after posts within your Twitter timeline.
The trigram appears at a staggered rate, approximating the frequency with which it shows up after lines in the 11th century epic poem The Song of Roland.
Do whatever you need to do with your browser of choice to add the contents of
roland.css to your custom local stylesheet. Then browse your timeline on twitter.com. Enjoy the mystery.
Faking randomization with nth-child, an article by Peter Gasston which informed a technique found in the CSS used here.
Shamefully, I cannot remember who taught the multiple-semester world literature course I took at the University of Maine in the middle 1990s, but I own the Norton textbook quoted above because of it.