1897 Paul Fischer Vilh. Soborgs Eft. Reklame-Plakater Paris Les maîtres de l'affiche
The pattern
This still is filed under Demonstration ad.
Define
The product does the arguing. The viewer sees the thing work, not a slogan about the thing working.
Mechanism
Proof by performance. The claim is the action: a visible, testable result the reader can replay.
Verdict
We can show a result in seconds
Why it works
The advertisement is placed inside the picture as an object the character is physically holding, so the copy is being read by someone in the scene before it is read by you. That makes the claim self-proving: you never have to be told the posters get attention, you watch one take a man out of a busy room. Fischer also puts the reading figure's back to you at the largest scale in the frame, so your sightline lands on the held sheet, which is the only white rectangle in a saturated composition.
Steal this when
Use this when your product's benefit is attention or persuasion and any direct claim would sound like boasting. Draw the product in use, held by someone absorbed in it, and let the surrounding crowd be visibly ignored.