What is double carp

Double carp: The ancients sent letters and formed the letters into the shape of double carp. Gu Yue Fu "drink horse caves of the Great Wall" : "Visitors from afar, left me double carp." Then he compared it to letters.

Tang Li Shangyin "send ling fox Lang" : "Song Yun Qin tree long away from home, double carp a paper book." "Double fish" is synonymous.

Tang Li Bai "to Hanyang assistant clerk" : "Hankou double fish white scales, make the ruler element reported lover."