The crime became so bad in Loisaida that its lettered avenues got nicknames.

VOA: special.2009.04.27

Where before it was two colored pairs now it's two lettered pairs .

之前用两种成对的颜色表示,现在是用两对字母GCTA表示

耶鲁公开课 - 生物医学工程探索课程节选