//5.6
/*
             +------------+                
             | FamilyTree |<--------------+
             +------------+               |
             +------------+               |
                   |                      |
                  / \                     |
                  ---                     |
                   |                      |
            ---------------------         |
            |                   |         |
  +-------------------+    +---------+    |
  | Person            |    | Unknown |    |
  +-------------------+    +---------+    |
  | String name       |    +---------+    |
  | int year          |                   |
  | FamilyTree mother |-+                 |
  | FamilyTree father |-+                 |
  +-------------------+ |                 |
                        |                 |
                        +-----------------+

*/

// To describe a Family tree
interface FamilyTree {
}

// To describe a person
class Person implements FamilyTree {
  String name;
  int year;
  FamilyTree mother;
  FamilyTree father;

  Person(String name, int year, FamilyTree mother, FamilyTree father) {
    this.name = name;
    this.year = year;
    this.mother = mother;
    this.father = father;
  }
}

// To describe and Unknown person
class Unknown implements FamilyTree {

  Unknown() {
  }
}

class Examples{
  Examples(){}
  FamilyTree unknown = new Unknown();
  Person claire = new Person("Claire", 1940, this.unknown, this.unknown);
  Person ray = new Person("Ray", 1939, this.unknown, this.unknown);
  Person emily = new Person("Emily", 1920, this.unknown, this.unknown);
  Person raphael = new Person("Raphael", 1917, this.unknown, this.unknown);
  Person debra = new Person("Debra", 1960, this.claire, this.ray);
  Person ralph = new Person("Ralph", 1958, this.emily, this.raphael);
  Person greg = new Person("Greg", 1989, this.debra, this.ralph);
  Person kenny = new Person("Kenny", 1992, this.debra, this.ralph);
  Person jeff = new Person("Jeff", 1996, this.debra, this.ralph);
  }