[6SixTy]

Braille typewriters are also very much like Stenography, except Braille is actually designed to replace reading & writing rather than transcribing speech.

Though Braille does use two dots for E and one for A, with mostly the same letter frequency in both it's native French and English.

Also very much surprised his keyboard didn't fit into either ASCII nor EBCDIC encoding. Granted, both of those barely existed at the time but still.