In 2013, the family of Marvin Gaye sued Robin Thicke, Pharrell and their label Universal for copyright infringement in a little song called “Blurred Lines.” It was alleged that the song veered too similar in vibe to Gaye’s 1977 track “Got to Give It Up.” Last December, Gaye’s estate won and was awarded the largest damages in music copyright history. Pharrell, Thicke and Universal have since filed an appeal this month. Intellectual property lawyer Foong Cheng Leong explains how much of a song can be copyrighted.