Well, sort of. In practice, the rings persist just long enough to make out a single letter. But you get the idea.
Chicagoan Mitchell F. Chan’s THE INGENIOUS GENTLEMAN DON QUIXOTE OF LA MANCHA is slowly evaporating the text of Cervantes’ famous novel into the air, one letter at a time. Mitch writes:
The clouds (actually vortex rings) are generated by ultrasonic and subsonic sounds. The canisters that shoot the clouds into the air are sequenced through an Arduino reading a .txt file of the whole book on MicroSD. With each letter, the clouds are emitted in a sequence similar to a row of LEDs on a ticker-tape display, so the letters are scrolling upwards, and each puff can be considered like a row of pixels.