This set of six different stamps, of which three have the same design in different colors, was issued in conjunction with a week-long promotion to stimulate the writing of more letters. The three stamps with identical designs, while smaller in size than the other three stamps, match the color schemes of those stamps and simply say, "P.S. Write Soon." Frequent letter writing is associated with beautiful handwriting. Calligraphy is the art of fine handwriting, which may refer to words, letters, pages, or even whole documents to which aesthetic principles and skilled penmanship have been applied.