A designer has earned more than $100,000 (£77,000) in less than a week, after posting a tweet showcasing his collection of iPhone app icons.
The creator, known online as Traf, says he produced "the right content, at the right time" and was boosted by tech-reviewing YouTube star Marques Brownlee.
Traf had noticed a trend of people sharing screenshots of their newly customised iPhone homescreens, with colour-coordinated icons and widgets.
While this was nothing unusual for users of Android smartphones, Apple had never officially let its users customise their iPhones in this way.
But after the launch of iOS 14 in September, users discovered a work-around that let them completely redesign their homescreens, changing app icons to whatever they liked.
It inspired Traf to share a screenshot of his own minimalistic monochrome design on Twitter.
It was an instant hit, with users describing it as "clean", "slick" and a "dream aesthetic". For many, it was a first taste of smartphone customisation.
"Right away, people started asking about the icons in the screenshot. So I quickly packaged them," he said in his blog.
Since there was "no notion of what an iOS icon set should be priced at", he decided to charge $28 (£22) for the set.
Many people replied that the icons were too expensive, but plenty of people were not deterred.
"I knew when I woke up the day after posting my icons for sale that they were going to do well, since I made a few grand in my sleep," he told the BBC.
Sales soared after YouTube star Marques Brownlee, who has more than 12 million subscribers to his technology review channel, showcased the icons.
Traf has now made more than $140,000 selling his icons to more than 5,000 customers.
The designer, who is currently based in San Francisco, called it an "unimaginable result".
But he said those hoping to emulate his success should not simply try to exploit online trends.
"If I had done this exclusively for the goal of making money, I'm convinced it wouldn't have worked nearly as well as it did," he explained.
"Keep working at the things you enjoy, share them with the world, and let the internet do the rest."
Speaking to the BBC, Mr Brownlee congratulated Traf for "capitalising on something new and making something great".