Morse code. In order to give the simplest codes to the letters used most often, he drew up a chart by counting the numbers of letters in sets of printers’ types. This put E at the top of the list, and Z, unsurprisingly, at the bottom – positions that are largely true to this day.
Why is M (two dashes) so simple? It scores 3 in Scrabble but is easier to send in Morse than the more frequently used O.
