Rules were made to be broken, especially in fashion. Only wear white between Memorial Day and Labor Day? No way. Don’t mix black and brown? Please.

But some rules are non-negotiables. These fashion guidelines have been put in place to protect poor, innocent bystanders from the most heinous of looks. Until now.

Socks and sandals, the hallmark of European tourists and sad dads everywhere are suddenly fashionable. From upscale open-toed heels paired with a mesh or frilly sock, to the highest of all fashion atrocities — wool socks worn with Birkenstocks — it’s all fair game now.

“People in fashion are always looking for something new, and appropriating other trends is really the only way to do that,” Gillian Fuller, 21, a fashion writer living in New York, said. “I don’t think it’s really possible to create something new, so designers take styles that are uncool or not normal and make it big because that’s the only way they can stay relevant.”

The atrocities began during the Spring 2010 runway shows. John Galliano sent models down the runway with iridescent mid-calf socks under open-toe platform sandals at Dior. Over in London, Christopher Bailey’s trenchcoat-clad models stomped down the Burberry runway in the only footwear accessory that makes sense for a rainy day in England — slouchy wool-blend socks with platform sandals.

But runway looks aren’t always intended for public consumption. No one started wearing the circular face-caging hats from the Alexander McQueen Spring 2013 collection, and certainly no one’s rocking the neon green Chewbacca-inspired bodysuit from Jeremy Scott’s Autumn/Winter 2013 collection—or maybe just not yet.

The fashion industry acts like a trickle-down economy: trends start at the top, at the ready-to wear presentations during New York, London, Milan and Paris fashion weeks. Then the mid-level shops such as Sandro or French Connection catch on, then fast fashion retailers including Zara down to Forever 21 glom on and mass produce the trend to death. And then it’ll show up giant circular racks in Target.

Right now the trend currently sits somewhere between steps two and three, with fashion-types such as bloggers and designers taking part. The Row designers Mary-Kate and Ashley Olsen showed off their Birkenstock and slouch sock look at an airport in March, and the trend was in full force during Fashion Week in New York in February.

“I actually haven’t seen a lot of people wearing the trend in New York,” Elizabeth Denton, a web editor at Seventeen Magazine, said. “I have seen it more during Fashion Week, when the street-style girls have come out to try to get their photo taken and they will rock as many trends as they can.”

But according to Denton, socks and sandals may not be as fleeting as one may hope.

“It never really goes away but every few seasons, a few designers do it and it becomes a trend again,” Denton said. “It’s super cute on the right person and the right sock and sandal combo, but that’s very hard to do. It works better on someone under 25, with higher heels, and very lightweight socks — American Apparel sells the perfect ones.”

Socks and sandals are just one facet of another slightly controversial trend in fashion currently.

“It’s all related. Birkenstocks and other ‘ugly’ shoes are part of the normcore trend,” Denton said. “I love it! It’s the first comfortable trend in forever. You have to really go for it, though. If you half-ass it and wear shoes that look orthopedic-like with jeans and a tee, you will just look you don’t know how to dress.”

Normcore, or rather #normcore, took the Internet by storm in February when New York Magazine wrote an article on the topic, calling it “fashion for those who realize they’re one in seven billion,” giving a name to the “art kids” in Soho wearing fleece quarter-zip pullovers and “dad jeans” as a fashion statement. Is it a trend or a joke? No one’s quite figured it out yet, but fashion mags like Lucky have created slideshows filled with entry-level normcore looks, so it’s likely things have already gone too far.

“Normcore is a thing that’s always been around in my eyes. It just now has a hashtag around it,” Ashley Marchi, 24, agent assistant at a music booking agency in Chicago, said. “I think the definition of normcore is something open to opinion. To some, it’s dressing like a cool dad on vacation. To others, it’s whatever the Gap has been selling since the ’80s. The word has taken on a negative connotation thanks to the Internet.”

For Marchi, though, socks and sandals are still the more serious offense.

“The only time I found socks and sandals to be appropriate was going to and from practice when you needed to change into cleats,” Marchi said. “I used to do it for softball practice and even I wanted to make fun of myself for it. Otherwise, it’s incredibly lazy and very tacky, especially in an urban setting like Chicago.”

Even if it’s tacky in an urban setting, it seems as though the trend is firmly planted in city life.

“I think it’s a city-only trend, for sure,” Denton said. “Though hopefully there will be a few teens rocking the trend in their small towns.”

As of right now, that has yet to be seen.

Emily Karnick, 22, of Aurora., said the only time she’s seen the trend worn is by her Polish extended family.

“Being Polish I guess it’s a part of my culture or something, so it doesn’t really shock me,” Karnick said. “But I would never wear (socks and sandals), whether trying to be fashionable or not.”