Just as clicking the “on” button of a remote control sends the TV a “message” to turn itself on, in Kay’s system one sends the object “3” the message “+ 4.” The object knows to interpret that as a simple addition, and returns 7. This may seem complex at first. But in contrast to traditional languages, object-oriented programming becomes relatively simpler as the data and operations become more complex. The reason is that the underlying calculations always remain hidden within the object, never needing to be explicitly invoked by the programmer. The object “John,” for example, needs only to be
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