Ivory Soap ... It Floats" - illustrated by Alice Beach Winter (Saturday Evening Post, Jan 7 1911)
The pattern
This still is filed under Iconic figure claim.
Define
A single figure, drawn, silhouetted, or posed, is the whole claim. You can read it across a street.
Mechanism
Compression into a body. The figure is not decoration. It is the sentence. Distance-legibility is the test.
Verdict
Poster scale, outdoor, packaging at a glance
Why it works
A manufacturing accident is converted into a use case: it floats is a product fact, and the letter turns it into the one reason a mother would switch brands this week. Putting the anecdote in a customer's voice and labelling it as an extract from a letter lets the ad make a big claim without the advertiser asserting it, and the neighbour's line about airships measures the product against the era's most impressive technology. The illustration shows the outcome rather than the product, so the copy only has to confirm what the picture has already sold, and the closing panel can stay short and flat.
Steal this when
When your product has an odd physical property that looks irrelevant, find the single domestic situation where it solves something, and let a customer's own letter tell that story instead of writing a benefit line. Strongest when the artwork can show the moment of relief rather than the product.