It is important that objects be allowed to perform their task however
they see fit, without unnecessary interactions or interference with
other objects.
``Instead of a bit-grinding processor ... plundering data structures,
we have a universe of well-behaved object that courteously ask each other
to carry out their various desires'' -- Dan Ingalls.
``Ask not what you can do to your data structures, but ask what your data structures can do for you''