I had this in mind when I visited a friend of long standing a few nights ago. His father was, apparently, an excellent typewriter mechanic, and he happened to be there the same night. Although now nearly eighty, he's still sprightly and reads without glasses. So I took the opportunity to download the long form birth certificate and asked him whether it had been drawn up on the same typewriter. He examined for no more than a few seconds before confidently stating 'no, no, at least three machines in use here'. Now you must understand that he had virtually no knowledge of the significance of what I was driving at. He saw it just as a document which clearly had been drawn up on a number of machines.
'Why would they want to do that?' he asked me.