There is a good explanation of this on Wikipedia: - http://en.wikipedia.org/wiki/Circle-ellipse_problem http://en.wikipedia.org/wiki/Circle-ellipse_problem -

There is a good explanation of this on Wikipedia: - http://en.wikipedia.org/wiki/Circle-ellipse_problem http://en.wikipedia.org/wiki/Circle-ellipse_problem - http://en.wikipedia.org/wiki/Liskov_substitution_principle#A_typical_violation http://en.wikipedia.org/wiki/Liskov_substitution_principle#A...