2-level papertape is exceptional in that a symbol is not represented by a single row of punches but by multiple rows. This is the Godfather of papertape and invented by Sir Charles Wheatstone around 1850. It was used to punch morse code messages. I have seen different (conflicting) accounts of it, in most a morse dot is represented by a punch on one side while a dash is represented by a punch on the other side. Letter spacing was done by a single blank row, word spacing by three successive blank rows. Another account I have seen mentions that a dot is represented by a punch on both sides in the same row while a dash is represented by a punch on one side followed by a punch on the other side in the next row. It may be possible that both have been used. Also the actual morse coding used I do not know, in the section about Morse I give quite a few codings, but I have seen a photograph (?) of a piece of papertape that can not be deciphered with any of those codings.