We've reached the mark during New York Fashion Week where we can't seem to remember what day it is, but at least our outfits are still on point. Over the past five days, the fashion crowd's sartorial choices have struck a balance between fashion and function for running between shows in the middle of winter. On Monday, we learned that the humble turtleneck is a street style essential during this time of year. Not only does it serve a very important purpose — warmth! — but it's extremely versatile, too. The cozy garment was everywhere and came in many forms, from slouchy, chunky knit styles draped over flowing skirts or roomy pants, to a more structured version tucked into jeans or layered underneath a statement coat.