diff --git a/src/class.js b/src/class.js
index e7a0a2b..c885741 100644
--- a/src/class.js
+++ b/src/class.js
@@ -23,6 +23,35 @@
 
 /* eslint-disable no-undef */
 
+class User {
+  constructor(options) {
+    this.email = options.email;
+    this.password = options.password;
+  }
+  comparePasswords(potentialPassword) {
+    return this.password === potentialPassword;
+  }
+}
+
+class Animal {
+  constructor(options) {
+    this.age = options.age;
+  }
+  growOlder() {
+    return this.age += 1;
+  }
+}
+
+class Cat extends Animal {
+  constructor(options, name) {
+    super(options);
+    this.name = name;
+  }
+  meow() {
+    return `${this.name} meowed!`;
+  }
+}
+
 module.exports = {
   User,
   Cat,
diff --git a/src/prototype.js b/src/prototype.js
index e2494a6..2ffba08 100644
--- a/src/prototype.js
+++ b/src/prototype.js
@@ -51,6 +51,80 @@
 
 /* eslint-disable no-undef */
 
+function GameObject(gameObjProps) {
+  this.createdAt = gameObjProps.createdAt;
+  this.dimensions = gameObjProps.dimensions;
+}
+
+GameObject.prototype.destroy = function () {
+  return 'Game object was removed from the game.';
+};
+
+const someGameObj = new GameObject({
+  createdAt: new Date(),
+  dimensions: {
+    length: 2,
+    width: 1,
+    height: 1,
+  },
+});
+
+function NPC(gameObjProps) {
+  GameObject.call(this, gameObjProps);
+  this.hp = gameObjProps.hp;
+  this.name = gameObjProps.name;
+}
+
+NPC.prototype = Object.create(GameObject.prototype);
+
+NPC.prototype.takeDamage = function () {
+  return `${this.name} took damage.`;
+};
+
+const someNpcObj = new NPC({
+  createdAt: new Date(),
+  dimensions: {
+    length: 2,
+    width: 1,
+    height: 1,
+  },
+  hp: 5,
+  name: 'Hamster Huey',
+});
+
+someNpcObj.takeDamage();
+
+function Humanoid(gameObjProps) {
+  NPC.call(this, gameObjProps);
+  this.faction = gameObjProps.faction;
+  this.weapons = gameObjProps.weapons;
+  this.language = gameObjProps.language;
+}
+
+Humanoid.prototype = Object.create(NPC.prototype);
+
+Humanoid.prototype.greet = function () {
+  return `${this.name} offers a greeting in ${this.language}.`;
+};
+
+const hamsterHuey = new Humanoid({
+  createdAt: new Date(),
+  dimensions: {
+    length: 2,
+    width: 1,
+    height: 1,
+  },
+  hp: 5,
+  name: 'Hamster Huey',
+  faction: 'Gooey Kablooie',
+  weapons: [
+    'bubblegum',
+  ],
+  language: 'Hamsterish',
+});
+
+hamsterHuey.greet();
+
 module.exports = {
   GameObject,
   NPC,
diff --git a/src/recursion.js b/src/recursion.js
index 117db24..462b10e 100644
--- a/src/recursion.js
+++ b/src/recursion.js
@@ -3,17 +3,44 @@
 const nFibonacci = (n) => {
   // fibonacci sequence: 1 2 3 5 8 13 ...
   // return the nth number in the sequence
+  let result = 1;
+  let prevNum = 1;
+  const helper = (num) => {
+    if (n === 0) return;
+    prevNum = result;
+    result = num;
+    n -= 1;
+    return helper(result + prevNum);
+  };
+  helper(result);
+  return result;
 };
 
+// or const nFibonacci = n => n < 2 ? 1 : nFibonacci(n - 2) + nFibonacci(n - 1);
+
 const nFactorial = (n) => {
   // factorial example: !5 = 5 * 4 * 3 * 2 * 1
   // return the factorial of `n`
+  return n === 0 ? 1 : nFactorial(n - 1) * n;
 };
 
 /* Extra Credit */
 const checkMatchingLeaves = (obj) => {
   // return true if every property on `obj` is the same
   // otherwise return false
+  const vals = [];
+  const helper = (newObj) => {
+    const props = Object.keys(newObj);
+    props.forEach((prop) => { // or !!newObj[prop] && newObj[prop].constructor === Object or Object(newObj[prop]) === newObj[prop]
+      if (typeof newObj[prop] === 'object' && newObj[prop] !== null && !Array.isArray(newObj[prop])) {
+        helper(newObj[prop]);
+        return;
+      }
+      vals.push(newObj[prop]);
+    });
+  };
+  helper(obj);
+  return vals.every(val => val === vals[0]);
 };
 
 /* eslint-enable no-unused-vars */
diff --git a/src/this.js b/src/this.js
index f0f994c..ac05c8e 100644
--- a/src/this.js
+++ b/src/this.js
@@ -7,6 +7,11 @@
 class User {
   constructor(options) {
     // set a username and password property on the user object that is created
+    this.username = options.username;
+    this.password = options.password;
+  }
+  checkPassword(passwordToCompare) {
+    return this.password === passwordToCompare;
   }
   // create a method on the User class called `checkPassword`
   // this method should take in a string and compare it to the object's password property
@@ -19,7 +24,6 @@ const me = new User({
 });
 
 const result = me.checkPassword('correcthorsebatterystaple'); // should return `true`
-
 /* part 2 */
 
 const checkPassword = function comparePasswords(passwordToCompare) {
@@ -27,13 +31,15 @@ const checkPassword = function comparePasswords(passwordToCompare) {
   // use `this` to access the object's `password` property.
   // do not modify this function's parameters
   // note that we use the `function` keyword and not `=>`
+  return this.password === passwordToCompare;
 };
 
 // invoke `checkPassword` on `me` by explicitly setting the `this` context
 // use .call, .apply, and .bind
-
 // .call
-
 // .apply
-
 // .bind
+checkPassword.call(me, 'correcthorsebatterystaple');
+checkPassword.apply(me, ['correcthorsebatterystaple']);
+const boundCheckPassword = checkPassword.bind(me);
+boundCheckPassword('correcthorsebatterystaple');