It started with backlash for a startup’s ad campaign. But overnight Monday, one engineer managed to reverse that negativity into a positive and then viral movement on Twitter with the hashtag #ILookLikeAnEngineer and photos of smiling women and men.

It started with Isis Wenger. She’s a full-stack engineer at OneLogin in San Francisco and is one of the new cover girls for her company’s recruiting campaign. Not all riders on San Francisco’s public transportation were pleased with her “sexy smirk” in the ads -- at least that’s what she gathered from the berating messages her friends came across and sent her way, TechCrunch reports.

So Wenger took to blogging site Medium to explain what the campaign was and who she is. “I’m pretty blown away at the amount of attention my ad particularly has received,” she wrote. “I didn’t want or ask for any of this attention, but if I can use this to put a spotlight on gender issues in tech I consider that to be at least one win.”

In a well-crafted piece, Wenger shares the ways she’s been harassed at work and other negative trends she’s witnessed or heard about in the tech industry. But more than just airing her grievances, Wenger ended her piece by encouraging others to join in the conversation and spread “redefine what an engineer should look like” by using the hashtag #ILookLikeAnEngineer.

From Monday night into Tuesday morning, nearly 18,000 tweets were sent as part of the viral campaign. Some tweets came from high-profile executives in the tech industry. Others were from startup workers and engineering students.

While Twitter struggles to please Wall Street on user growth numbers and there’s been talk of an acquisition, one thing is for sure: The hashtag can still be used to propel positive conversations. After the Supreme Court's same-sex marriage ruling in June, the hashtag #LoveWins took off with a tweet from U.S. President Barack Obama and has since gone offline to posters, T-shirts and cheering voices.

Wengler and the community she's helped form have continued to build up the movement. For example, Wengler bought the domain name And someone's already made the T-shirts.