Multiple ties
From Futurepedia, the Back to the Future Wiki
In 2015, it was customary for one to wear multiple ties, with business suits. To an observer from an earlier era, it would appear at first glance that the wearer had put on two identical neckties, each with its own knot. On closer inspection, however, one would note that the two ties were separated by an addition to the middle of the shirt collar. Known wearers of multiple ties included Marty McFly and Ito Fujitsu. Terry wore a striped multiple tie whose two lengths wrapped around him like a vest. The multiple tie was different than the transparent necktie, something which Doc was wearing when he picked up Marty and Jennifer in 1985.
