In 1978, a Harvard Business School student named Dan Bricklin was sitting in a classroom, watching his accounting lecturer filling in rows and columns on the blackboard. Every time the lecturer changed a figure, he had to work down and across the grid on the board, erasing and rewriting other numbers to make everything add up, just as accounting clerks all over the world did every day in the pages of their ledgers. It's boring and repetitive work. A two-page spread across the open fold of the ledger is called a "spreadsheet". --- It's a cliche that the robots are...