Why functional over OO? https://medium.com/@cscalfani/goodbye-object-oriented-programming-a59cda4c0e53 Inheritance Banana Monkey Jungle The diamond relationship Fragile parent class Categorical (Taxonomy) v. Containment (or Exclusive Ownership) Hierarchies Encapsulation Object passed by reference to an Object Constructor is not safe Deep cloning MC Hammer v. Immutability Global Scope Polymorphism https://www.cs.utexas.edu/~mitra/csSummer2013/cs312/lectures/interfaces.html Design by Behavior not Data