object lesson

plural object lessons

1. A lesson taught (especially to young children) using a familiar or unusual object as a focus.
2. An example from real life that explains a principle or teaches a lesson.

   Vertebrates are limited to two eyes each, but the variations they have played on this plain vanilla starting point are an object lesson in how much can be made from a little.

   2012, Caspar Henderson, The Book of Barely Imagined Beings, page 107

3. Anything used as an example or lesson which serves to warn others as to the outcomes that result from a particular action or behavior, as exemplified by the fates of those who followed that course.

   Let that be an object lesson to him.

   4 more examples

   Of the announcement, Osborne said: "They have spent a hundred billion pounds of public money and they've got a massive raspberry from everyone as far as I can see. As a PR exercise, it's been an object lesson in how not to make a government announcement."

   2021 December 1, “Network News: Integrated Rail Plan: Osborne predicts HS2 eastern leg will return”, in RAIL, number 945, page 8

   Yet China, like Russia, is now giving us an object lesson in the usefulness of having an open society, where strongmen don’t get to invent their own reality.

   2022 March 17, Paul Krugman, “Another Dictator Is Having a Bad Year”, in The New York Times, →ISSN

   The U.K. is now an object lesson for other countries dealing with a dark triad of deindustrialization, degrowth, and denigration of foreigners.

   2022 October 25, Derek Thompson, “How the U.K. Became One of the Poorest Countries in Western Europe”, in The Atlantic

   Thames Water has become the latest object lesson in the predictable and predicted folly of privatised monopolies, aided by a regulator that’s an even bigger wet wipe than the fatbergs bunging up the sewers.

   2023 June 30, Marina Hyde, “The tide is coming in fast on Rishi Sunak – and it’s full of sewage”, in The Guardian