A few months ago Anna Gensler, an artist friend of mine who lives in Maryland, downloaded an online dating app called Tinder. This probably means nothing to anyone over the age of 30 (ie most Financial Times readers). But Tinder is wildly popular among young Americans and a growing international audience since it enables them to post brief dating profiles pulled from their Facebook accounts. Users then typically use these to chat and hunt for dates – usually harmlessly.

However, the app also has a seedier side: Tinder can be used to arrange sex hookups. And when she joined, Gensler was quickly bombarded by lewd messages; instead of initiating conversations with “hello”, men made contact with exceptionally graphic, misogynist, sexual comments.

So Gensler took revenge. She posted a note on her profile warning that if anyone sent offensive greetings, she would draw a nude cartoon of them based on their photos. Then, when the messages kept arriving, she duly scribbled portraits of the men, sent them back and posted these on her Instagram page alongside the men’s messages.