Forget Tesla vs. Edison. Remember Kettering, whose hack revolutionized cars.

While true, there are many hundreds of people who "revolutionized" cars. Even with starter motors, it had to be married to Bendix's method for engaging and disengaging the starter motor automatically, in order to complete the transformation over to electric starters.

Or there's Florence Lawrence, "The First Movie Star", who created the turn indicator and a brake indicator (a 'stop' sign) activated by applying the foot brake.

(And http://www.history.com/this-day-in-history/silent-film-star-... points out that Lawrence's mother invented the first electrical windshield wipers.)

So, separation of concerns, encapsulation, and DRY. Day one of OO programming 101.