The hard part was standing stock-still for a whole minute of exposure.
I'm reading a book about zero gravity... I just can't put it down.
I once considered creating a grading system for character sets used this way, so that software could be written around it. I initially saw it being used to translate data digitised by hand using contemporary mechanical methods, then later automatic methods could be developed.
The one I showed above was created recently with software from a photo.
