BrainBuster Answer

This beautiful U.S. Flag stamp, first issued in 1957, has a very important
distinction that has to do with the way it was printed. What is it!

This line-engraved bicolor stamp
was the first United States stamp printed on the
world famous (and amazing) Giori color printing press that,
in effect, allowed all of its colors to be printed simultaneously
instead of one color at a time.