Prevention is key when it comes to tackling Griswold-style holiday light knots.It?s easy to wrap a strand around your forearm, toss it in a basement bin and ring in the new year. But next season, you?ll have to deal with the rat-king tangles of your own making.For the final life hack investigation of 2017, we tested three different methods of wrapping up a 50-light string about five metres long. Pull out your coat...