diff --git a/Chapter01/Chapter01-mac.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist b/Chapter01/Chapter01-mac.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist
new file mode 100644
index 00000000..18d98100
--- /dev/null
+++ b/Chapter01/Chapter01-mac.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>
diff --git a/Chapter01/Game.cpp b/Chapter01/Game.cpp
index 3b18199e..e9bad05f 100644
--- a/Chapter01/Game.cpp
+++ b/Chapter01/Game.cpp
@@ -10,13 +10,15 @@
 
 const int thickness = 15;
 const float paddleH = 100.0f;
+const int numBalls = 2;
 
 Game::Game()
 :mWindow(nullptr)
 ,mRenderer(nullptr)
 ,mTicksCount(0)
 ,mIsRunning(true)
-,mPaddleDir(0)
+,mPaddleLeftDir(0)
+,mPaddleRightDir(0)
 {
 	
 }
@@ -60,12 +62,27 @@ bool Game::Initialize()
 		return false;
 	}
 	//
-	mPaddlePos.x = 10.0f;
-	mPaddlePos.y = 768.0f/2.0f;
-	mBallPos.x = 1024.0f/2.0f;
-	mBallPos.y = 768.0f/2.0f;
-	mBallVel.x = -200.0f;
-	mBallVel.y = 235.0f;
+	mPaddleLeftPos.x = 10.0f;
+	mPaddleLeftPos.y = 768.0f/2.0f;
+    
+    mPaddleRightPos.x = 1024.0f - 10.0 - thickness;
+    mPaddleRightPos.y = mPaddleLeftPos.y;
+    
+    mBalls = std::vector<Ball>(numBalls);
+    
+    for(int i=0; i<numBalls; i++) {
+        Ball ball;
+        
+        float divisor = float(i+1);
+        ball.position.x = 1024.0f/divisor;
+        ball.position.y = 768.0f/divisor;
+        // alternate balls in opposite directions
+        ball.velocity.x = 200.0f * (i % 2 ? 1 : -1);
+        ball.velocity.y = 235.0f;
+        
+        mBalls[i] = ball;
+    }
+    
 	return true;
 }
 
@@ -102,15 +119,26 @@ void Game::ProcessInput()
 	}
 	
 	// Update paddle direction based on W/S keys
-	mPaddleDir = 0;
+	mPaddleLeftDir = 0;
 	if (state[SDL_SCANCODE_W])
 	{
-		mPaddleDir -= 1;
+		mPaddleLeftDir -= 1;
 	}
 	if (state[SDL_SCANCODE_S])
 	{
-		mPaddleDir += 1;
+		mPaddleLeftDir += 1;
 	}
+    
+    // Update paddle direction based on I/K keys
+    mPaddleRightDir = 0;
+    if (state[SDL_SCANCODE_I])
+    {
+        mPaddleRightDir -= 1;
+    }
+    if (state[SDL_SCANCODE_K])
+    {
+        mPaddleRightDir += 1;
+    }
 }
 
 void Game::UpdateGame()
@@ -133,61 +161,81 @@ void Game::UpdateGame()
 	mTicksCount = SDL_GetTicks();
 	
 	// Update paddle position based on direction
-	if (mPaddleDir != 0)
+	if (mPaddleLeftDir != 0)
 	{
-		mPaddlePos.y += mPaddleDir * 300.0f * deltaTime;
+		mPaddleLeftPos.y += mPaddleLeftDir * 300.0f * deltaTime;
 		// Make sure paddle doesn't move off screen!
-		if (mPaddlePos.y < (paddleH/2.0f + thickness))
+		if (mPaddleLeftPos.y < (paddleH/2.0f + thickness))
 		{
-			mPaddlePos.y = paddleH/2.0f + thickness;
+			mPaddleLeftPos.y = paddleH/2.0f + thickness;
 		}
-		else if (mPaddlePos.y > (768.0f - paddleH/2.0f - thickness))
+		else if (mPaddleLeftPos.y > (768.0f - paddleH/2.0f - thickness))
 		{
-			mPaddlePos.y = 768.0f - paddleH/2.0f - thickness;
+			mPaddleLeftPos.y = 768.0f - paddleH/2.0f - thickness;
 		}
 	}
+    
+    if (mPaddleRightDir != 0)
+    {
+        mPaddleRightPos.y += mPaddleRightDir * 300.0f * deltaTime;
+        if (mPaddleRightPos.y < (paddleH/2.0f + thickness))
+        {
+            mPaddleRightPos.y = paddleH/2.0f + thickness;
+        }
+        else if (mPaddleRightPos.y > (768.0f - paddleH/2.0f - thickness))
+        {
+            mPaddleRightPos.y = 768.0f - paddleH/2.0f - thickness;
+        }
+    }
 	
-	// Update ball position based on ball velocity
-	mBallPos.x += mBallVel.x * deltaTime;
-	mBallPos.y += mBallVel.y * deltaTime;
-	
-	// Bounce if needed
-	// Did we intersect with the paddle?
-	float diff = mPaddlePos.y - mBallPos.y;
-	// Take absolute value of difference
-	diff = (diff > 0.0f) ? diff : -diff;
-	if (
-		// Our y-difference is small enough
-		diff <= paddleH / 2.0f &&
-		// We are in the correct x-position
-		mBallPos.x <= 25.0f && mBallPos.x >= 20.0f &&
-		// The ball is moving to the left
-		mBallVel.x < 0.0f)
-	{
-		mBallVel.x *= -1.0f;
-	}
-	// Did the ball go off the screen? (if so, end game)
-	else if (mBallPos.x <= 0.0f)
-	{
-		mIsRunning = false;
-	}
-	// Did the ball collide with the right wall?
-	else if (mBallPos.x >= (1024.0f - thickness) && mBallVel.x > 0.0f)
-	{
-		mBallVel.x *= -1.0f;
-	}
-	
-	// Did the ball collide with the top wall?
-	if (mBallPos.y <= thickness && mBallVel.y < 0.0f)
-	{
-		mBallVel.y *= -1;
-	}
-	// Did the ball collide with the bottom wall?
-	else if (mBallPos.y >= (768 - thickness) &&
-		mBallVel.y > 0.0f)
-	{
-		mBallVel.y *= -1;
-	}
+    for(auto &ball : mBalls) {
+        // Update ball position based on ball velocity
+        ball.position.x += ball.velocity.x * deltaTime;
+        ball.position.y += ball.velocity.y * deltaTime;
+        
+        // Bounce if needed
+        // Did we intersect with the paddle?
+        float diffL = mPaddleLeftPos.y - ball.position.y;
+        float diffR = mPaddleRightPos.y - ball.position.y;
+        
+        // Take absolute value of difference
+        diffL = (diffL > 0.0f) ? diffL : -diffL;
+        diffR = (diffR > 0.0f) ? diffR : -diffR;
+        if (
+            // Our y-difference is small enough
+            diffL <= paddleH / 2.0f &&
+            // We are in the correct x-position
+            ball.position.x <= 25.0f && ball.position.x >= 20.0f &&
+            // The ball is moving to the left
+            ball.velocity.x < 0.0f)
+        {
+            ball.velocity.x *= -1.0f;
+        }
+        else if (
+                 diffR <= paddleH / 2.0f &&
+                 ball.position.x >= 1024.0f - 25.0f && ball.position.x >= 1024.0f - 20.0f &&
+                 ball.velocity.x > 0.0f)
+        {
+            ball.velocity.x *= -1.0f;
+        }
+        // Did the ball go off the screen? (if so, end game)
+        else if (ball.position.x <= 0.0f || ball.position.x >= 1024.0f)
+        {
+            mIsRunning = false;
+        }
+        
+        // Did the ball collide with the top wall?
+        if (ball.position.y <= thickness && ball.velocity.y < 0.0f)
+        {
+            ball.velocity.y *= -1;
+        }
+        // Did the ball collide with the bottom wall?
+        else if (ball.position.y >= (768 - thickness) &&
+                 ball.velocity.y > 0.0f)
+        {
+            ball.velocity.y *= -1;
+        }
+    }
 }
 
 void Game::GenerateOutput()
@@ -220,30 +268,33 @@ void Game::GenerateOutput()
 	wall.y = 768 - thickness;
 	SDL_RenderFillRect(mRenderer, &wall);
 	
-	// Draw right wall
-	wall.x = 1024 - thickness;
-	wall.y = 0;
-	wall.w = thickness;
-	wall.h = 1024;
-	SDL_RenderFillRect(mRenderer, &wall);
-	
 	// Draw paddle
-	SDL_Rect paddle{
-		static_cast<int>(mPaddlePos.x),
-		static_cast<int>(mPaddlePos.y - paddleH/2),
+	SDL_Rect paddleL{
+		static_cast<int>(mPaddleLeftPos.x),
+		static_cast<int>(mPaddleLeftPos.y - paddleH/2),
 		thickness,
 		static_cast<int>(paddleH)
 	};
-	SDL_RenderFillRect(mRenderer, &paddle);
+	SDL_RenderFillRect(mRenderer, &paddleL);
+    
+    SDL_Rect paddleR{
+        static_cast<int>(mPaddleRightPos.x),
+        static_cast<int>(mPaddleRightPos.y - paddleH/2),
+        thickness,
+        static_cast<int>(paddleH)
+    };
+    SDL_RenderFillRect(mRenderer, &paddleR);
 	
-	// Draw ball
-	SDL_Rect ball{	
-		static_cast<int>(mBallPos.x - thickness/2),
-		static_cast<int>(mBallPos.y - thickness/2),
-		thickness,
-		thickness
-	};
-	SDL_RenderFillRect(mRenderer, &ball);
+    for(const auto &ball : mBalls) {
+        // Draw ball
+        SDL_Rect ballRect{
+            static_cast<int>(ball.position.x - thickness/2),
+            static_cast<int>(ball.position.y - thickness/2),
+            thickness,
+            thickness
+        };
+        SDL_RenderFillRect(mRenderer, &ballRect);
+    }
 	
 	// Swap front buffer and back buffer
 	SDL_RenderPresent(mRenderer);
diff --git a/Chapter01/Game.h b/Chapter01/Game.h
index 3d59a468..29962c6d 100644
--- a/Chapter01/Game.h
+++ b/Chapter01/Game.h
@@ -8,6 +8,7 @@
 
 #pragma once
 #include "SDL/SDL.h"
+#include <vector>
 
 // Vector2 struct just stores x/y coordinates
 // (for now)
@@ -17,6 +18,12 @@ struct Vector2
 	float y;
 };
 
+struct Ball
+{
+    Vector2 position;
+    Vector2 velocity;
+};
+
 // Game class
 class Game
 {
@@ -44,12 +51,14 @@ class Game
 	bool mIsRunning;
 	
 	// Pong specific
-	// Direction of paddle
-	int mPaddleDir;
+	// Direction of left player paddle
+	int mPaddleLeftDir;
 	// Position of paddle
-	Vector2 mPaddlePos;
-	// Position of ball
-	Vector2 mBallPos;
-	// Velocity of ball
-	Vector2 mBallVel;
+	Vector2 mPaddleLeftPos;
+    
+    // Direction of right player paddle
+    int mPaddleRightDir;
+    Vector2 mPaddleRightPos;
+    
+    std::vector<Ball> mBalls;
 };