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Flexibiltiy    use me so that your software can change and grow without constant rework , i keep your application from being fragile

Encapsulation   you use me  to keep the parts of your code that stay the same seperate from the parts that change , then it's really    easy  to make changes  to your code without  breaking everything

Functionality    without me you'll never actually  make the customer happy  No matter how well-designed your application is .i'm the thing that puts a smile on the customer's face

Designer pattern      i'm all about resue and making sure that you're not trying to solve a problem that someone else has already figured out