The Wikipedia section is pretty good now. There are a few notable omissions. The backslash was added so that logical ∧ and ∨ could be written as /\ and \/ — two

The Wikipedia section is pretty good now. There are a few notable omissions. The backslash was added so that logical ∧ and ∨ could be written as /\ and \/ — two operators for the price of one. The characters : and ; were considered the least important punctuation, so they were placed immediately after 9, where they could be replaced by single-character 10 and 11 for shillings. And the characters *+,-./ were placed in rows 10-15 so that they could easily be combined with the digits to make a 16-bit subset suitable for writing numbers and basic arithmetic.