diff --git a/Tic-Tac-Toe/src/main/Board.java b/Tic-Tac-Toe/src/main/Board.java
index 203a3d6..bc78f9b 100644
--- a/Tic-Tac-Toe/src/main/Board.java
+++ b/Tic-Tac-Toe/src/main/Board.java
@@ -3,10 +3,11 @@ package main;
 public class Board {
 
 	private char[][] board;
-	private final int BOARD_SIZE = 4;
+	private final int BOARD_SIZE;
 	private char[][] symbols;
 
 	public Board() {
+		BOARD_SIZE = Options.boardSize;
 		board = new char[BOARD_SIZE * 3 + 1][BOARD_SIZE * 3 + 1];
 		for (int x = 0; x < board.length; x++) {
 			for (int y = 0; y < board[0].length; y++) {
@@ -52,12 +53,12 @@ public class Board {
 	}
 
 	public char testWinner() {
-		for (int x = 0; x < symbols.length - 1; x++) {
+		for (int x = 0; x < symbols.length; x++) {
 			if (symbols[x][0] == symbols[x][1] && symbols[x][0] == symbols[x][2] && symbols[x][0] != 0) {
 				return symbols[x][0];
 			}
 		}
-		for (int y = 0; y < symbols[0].length - 1; y++) {
+		for (int y = 0; y < symbols[0].length; y++) {
 			if (symbols[0][y] == symbols[1][y] && symbols[0][y] == symbols[2][y] && symbols[0][y] != 0) {
 				return symbols[0][y];
 			}
diff --git a/Tic-Tac-Toe/src/main/Cmd.java b/Tic-Tac-Toe/src/main/Cmd.java
new file mode 100644
index 0000000..c6e0a99
--- /dev/null
+++ b/Tic-Tac-Toe/src/main/Cmd.java
@@ -0,0 +1,14 @@
+package main;
+
+import java.io.IOException;
+
+public class Cmd {
+
+	public static void cls() {
+		try {
+			new ProcessBuilder("cmd", "/c", "cls").inheritIO().start().waitFor();
+		} catch (InterruptedException | IOException e) {
+			e.printStackTrace();
+		}
+	}
+}
diff --git a/Tic-Tac-Toe/src/main/Launcher.java b/Tic-Tac-Toe/src/main/Launcher.java
index 0937e33..4eece43 100644
--- a/Tic-Tac-Toe/src/main/Launcher.java
+++ b/Tic-Tac-Toe/src/main/Launcher.java
@@ -3,6 +3,7 @@ package main;
 public class Launcher {
 
 	public static void main(String[] args) {
+		Cmd.cls();
 		new MainMenu();
 	}
 }
diff --git a/Tic-Tac-Toe/src/main/MenuScreen.java b/Tic-Tac-Toe/src/main/MenuScreen.java
index 80a4dcf..cbcfbd9 100644
--- a/Tic-Tac-Toe/src/main/MenuScreen.java
+++ b/Tic-Tac-Toe/src/main/MenuScreen.java
@@ -28,8 +28,10 @@ public abstract class MenuScreen {
 					cursorPos++;
 				}
 			} else {
+				Cmd.cls();
 				select(cursorPos);
 			}
+			Cmd.cls();
 		}
 	}
 	
diff --git a/Tic-Tac-Toe/src/main/Options.java b/Tic-Tac-Toe/src/main/Options.java
index d5c0865..bbbfa42 100644
--- a/Tic-Tac-Toe/src/main/Options.java
+++ b/Tic-Tac-Toe/src/main/Options.java
@@ -2,9 +2,9 @@ package main;
 
 public class Options extends MenuScreen {
 	
-	public static char player1Symbol;
-	public static char player2Symbol;
-	public static int boardSize;
+	public static char player1Symbol = 'X';
+	public static char player2Symbol = 'O';
+	public static int boardSize = 4;
 
 	public Options() {
 		cursorPos = 0;
@@ -13,11 +13,6 @@ public class Options extends MenuScreen {
 		tabs[1] = "Player 2 symbol";
 		tabs[2] = "Spielfeldgröße";
 		tabs[3] = "Zurück";
-		
-		player1Symbol = 'X';
-		player2Symbol = 'O';
-		boardSize = 4;
-		
 		init();
 	}
 
@@ -31,15 +26,38 @@ public class Options extends MenuScreen {
 			player2Symbol = requestSymbol();
 			break;
 		case 2:
+			boardSize = requestNumber();
+			if (boardSize < 2) {
+				boardSize = 2;
+			}
+			if (boardSize % 2 == 1) {
+				boardSize++;
+			}
 			break;
 		case 3:
+			stopLoop();
 			break;
 		}
 	}
 	
+	private int requestNumber() {
+		System.out.println("Bitte gebe eine Zahl ein:");
+		String in = scanner.next();
+		while (!in.matches("[0-9]+")) {
+			System.out.println("Bitte eine Zahl eingeben!");
+			in = scanner.next();
+		}
+		return Integer.parseInt(in);
+	}
+	
 	private char requestSymbol() {
 		System.out.println("Bitte neues Symbol eingeben:");
-		return 0;
+		String in = scanner.next();
+		while (in.length() > 1) {
+			System.out.println("Bitte nur ein Symbol!");
+			in = scanner.next();
+		}
+		return in.charAt(0);
 		
 	}
 
@@ -54,7 +72,18 @@ public class Options extends MenuScreen {
 			} else {
 				System.out.print("   ");
 			}
-			System.out.println(tabs[i]);
+			System.out.print(tabs[i]);
+			switch (i) {
+			case 0:
+				System.out.println(": " + player1Symbol);
+				break;
+			case 1:
+				System.out.println(": " + player2Symbol);
+				break;
+			case 2:
+				System.out.println(": " + boardSize);
+				break;
+			}
 		}
 	}
 
diff --git a/Tic-Tac-Toe/src/main/PlayerAI.java b/Tic-Tac-Toe/src/main/PlayerAI.java
index 5530c00..4ec9c77 100644
--- a/Tic-Tac-Toe/src/main/PlayerAI.java
+++ b/Tic-Tac-Toe/src/main/PlayerAI.java
@@ -1,17 +1,285 @@
 package main;
 
 public class PlayerAI extends Player {
-	
+
 	private int nextMove;
 
 	public PlayerAI(char symbol) {
 		super(symbol);
 	}
-	
-	public void calculateNextMove(char[][] board) {
-		nextMove = 5;
+
+	public boolean calculateNextMove(char[][] board) {
+		int round = 0;
+		for (int x = 0; x < board.length; x++) {
+			for (int y = 0; y < board[0].length; y++) {
+				if (board[x][y] != 0) {
+					round++;
+				}
+			}
+		}
+		switch (round) {
+		case 0:
+			nextMove = 5;
+			return true;
+		case 1:
+			if (board[1][1] == 0) {
+				nextMove = 5;
+			} else {
+				int rand = (int) (Math.random() * 9) + 1;
+				if (rand % 2 == 0) {
+					rand++;
+				}
+				if (rand == 5) {
+					rand = 7;
+				}
+				nextMove = rand;
+			}
+			return true;
+		case 2:
+			if (board[1][0] != 0) {
+				nextMove = 3;
+				return true;
+			}
+			if (board[0][1] != 0) {
+				nextMove = 1;
+				return true;
+			}
+			if (board[2][1] != 0) {
+				nextMove = 9;
+				return true;
+			}
+			if (board[1][2] != 0) {
+				nextMove = 7;
+				return true;
+			}
+			break;
+		case 4:
+			if (board[0][0] == getSymbol()) {
+				nextMove = 3;
+				return true;
+			}
+			if (board[2][0] == getSymbol()) {
+				nextMove = 9;
+				return true;
+			}
+			if (board[0][2] == getSymbol()) {
+				nextMove = 1;
+				return true;
+			}
+			if (board[2][2] == getSymbol()) {
+				nextMove = 7;
+				return true;
+			}
+			break;
+		default:
+			if (!attack(board)) {
+				if (!block(board)) {
+					for (int i = 0; i < 8; i++) {
+						if (board[i % 3][i / 3] == 0) {
+							nextMove = i + 1;
+							return true;
+						}
+					}
+				}else {
+					return true;
+				}
+			}else {
+				return true;
+			}
+		}
+		return false;
 	}
 	
+	public boolean attack(char[][] board) {
+		if (board[0][0] == board[1][0] && board[0][0] == getSymbol() && board[0][0] != 0 && board[2][0] == 0) {
+			nextMove = 3;
+			return true;
+		} else if (board[0][1] == board[1][1] && board[0][1] == getSymbol() && board[0][1] != 0
+				&& board[2][1] == 0) {
+			nextMove = 6;
+			return true;
+		} else if (board[0][2] == board[1][2] && board[0][2] == getSymbol() && board[0][2] != 0
+				&& board[2][2] == 0) {
+			nextMove = 9;
+			return true;
+		} else if (board[1][0] == board[2][0] && board[1][0] == getSymbol() && board[1][0] != 0
+				&& board[0][0] == 0) {
+			nextMove = 1;
+			return true;
+		} else if (board[1][1] == board[2][1] && board[1][1] == getSymbol() && board[1][1] != 0
+				&& board[0][1] == 0) {
+			nextMove = 4;
+			return true;
+		} else if (board[1][2] == board[2][2] && board[1][2] == getSymbol() && board[1][2] != 0
+				&& board[0][2] == 0) {
+			nextMove = 7;
+			return true;
+
+		} else if (board[0][0] == board[0][1] && board[0][0] == getSymbol() && board[0][0] != 0
+				&& board[0][2] == 0) {
+			nextMove = 7;
+			return true;
+		} else if (board[1][0] == board[1][1] && board[1][0] == getSymbol() && board[1][0] != 0
+				&& board[1][2] == 0) {
+			nextMove = 8;
+			return true;
+		} else if (board[2][0] == board[2][1] && board[2][0] == getSymbol() && board[2][0] != 0
+				&& board[2][2] == 0) {
+			nextMove = 9;
+			return true;
+		} else if (board[0][1] == board[0][2] && board[0][1] == getSymbol() && board[0][1] != 0
+				&& board[0][0] == 0) {
+			nextMove = 1;
+			return true;
+		} else if (board[1][1] == board[1][2] && board[1][1] == getSymbol() && board[1][1] != 0
+				&& board[1][0] == 0) {
+			nextMove = 2;
+			return true;
+		} else if (board[2][1] == board[2][2] && board[2][1] == getSymbol() && board[2][1] != 0
+				&& board[2][0] == 0) {
+			nextMove = 3;
+			return true;
+
+		} else if (board[0][0] == board[1][1] && board[1][1] == getSymbol() && board[1][1] != 0
+				&& board[2][2] == 0) {
+			nextMove = 9;
+			return true;
+		} else if (board[0][2] == board[1][1] && board[1][1] == getSymbol() && board[1][1] != 0
+				&& board[2][0] == 0) {
+			nextMove = 3;
+			return true;
+		} else if (board[2][0] == board[1][1] && board[1][1] == getSymbol() && board[1][1] != 0
+				&& board[0][2] == 0) {
+			nextMove = 7;
+			return true;
+		} else if (board[2][2] == board[1][1] && board[1][1] == getSymbol() && board[1][1] != 0
+				&& board[0][0] == 0) {
+			nextMove = 1;
+			return true;
+			
+		} else if (board[0][0] == board[2][0] && board[0][0] == getSymbol() && board[0][0] != 0
+				&& board[1][0] == 0) {
+			nextMove = 2;
+			return true;
+		} else if (board[0][1] == board[2][1] && board[0][1] == getSymbol() && board[0][1] != 0
+				&& board[1][1] == 0) {
+			nextMove = 5;
+			return true;
+		} else if (board[0][2] == board[2][2] && board[0][2] == getSymbol() && board[0][2] != 0
+				&& board[1][2] == 0) {
+			nextMove = 8;
+			return true;
+		} else if (board[0][0] == board[0][2] && board[0][0] == getSymbol() && board[0][0] != 0
+				&& board[0][1] == 0) {
+			nextMove = 4;
+			return true;
+		} else if (board[1][0] == board[1][2] && board[1][0] == getSymbol() && board[1][0] != 0
+				&& board[1][1] == 0) {
+			nextMove = 5;
+			return true;
+		} else if (board[2][0] == board[2][2] && board[2][0] == getSymbol() && board[2][0] != 0
+				&& board[2][1] == 0) {
+			nextMove = 6;
+			return true;
+		}
+		return false;
+	}
+	
+	private boolean block(char[][] board) {
+		if (board[0][0] == board[1][0] && board[0][0] != getSymbol() && board[0][0] != 0 && board[2][0] == 0) {
+			nextMove = 3;
+			return true;
+		} else if (board[0][1] == board[1][1] && board[0][1] != getSymbol() && board[0][1] != 0
+				&& board[2][1] == 0) {
+			nextMove = 6;
+			return true;
+		} else if (board[0][2] == board[1][2] && board[0][2] != getSymbol() && board[0][2] != 0
+				&& board[2][2] == 0) {
+			nextMove = 9;
+			return true;
+		} else if (board[1][0] == board[2][0] && board[1][0] != getSymbol() && board[1][0] != 0
+				&& board[0][0] == 0) {
+			nextMove = 1;
+			return true;
+		} else if (board[1][1] == board[2][1] && board[1][1] != getSymbol() && board[1][1] != 0
+				&& board[0][1] == 0) {
+			nextMove = 4;
+			return true;
+		} else if (board[1][2] == board[2][2] && board[1][2] != getSymbol() && board[1][2] != 0
+				&& board[0][2] == 0) {
+			nextMove = 7;
+			return true;
+
+		} else if (board[0][0] == board[0][1] && board[0][0] != getSymbol() && board[0][0] != 0
+				&& board[0][2] == 0) {
+			nextMove = 7;
+			return true;
+		} else if (board[1][0] == board[1][1] && board[1][0] != getSymbol() && board[1][0] != 0
+				&& board[1][2] == 0) {
+			nextMove = 8;
+			return true;
+		} else if (board[2][0] == board[2][1] && board[2][0] != getSymbol() && board[2][0] != 0
+				&& board[2][2] == 0) {
+			nextMove = 9;
+			return true;
+		} else if (board[0][1] == board[0][2] && board[0][1] != getSymbol() && board[0][1] != 0
+				&& board[0][0] == 0) {
+			nextMove = 1;
+			return true;
+		} else if (board[1][1] == board[1][2] && board[1][1] != getSymbol() && board[1][1] != 0
+				&& board[1][0] == 0) {
+			nextMove = 2;
+			return true;
+		} else if (board[2][1] == board[2][2] && board[2][1] != getSymbol() && board[2][1] != 0
+				&& board[2][0] == 0) {
+			nextMove = 3;
+			return true;
+
+		} else if (board[0][0] == board[1][1] && board[1][1] != getSymbol() && board[1][1] != 0
+				&& board[2][2] == 0) {
+			nextMove = 9;
+			return true;
+		} else if (board[0][2] == board[1][1] && board[1][1] != getSymbol() && board[1][1] != 0
+				&& board[2][0] == 0) {
+			nextMove = 3;
+			return true;
+		} else if (board[2][0] == board[1][1] && board[1][1] != getSymbol() && board[1][1] != 0
+				&& board[0][2] == 0) {
+			nextMove = 7;
+			return true;
+		} else if (board[2][2] == board[1][1] && board[1][1] != getSymbol() && board[1][1] != 0
+				&& board[0][0] == 0) {
+			nextMove = 1;
+			return true;
+			
+		} else if (board[0][0] == board[2][0] && board[0][0] != getSymbol() && board[0][0] != 0
+				&& board[1][0] == 0) {
+			nextMove = 2;
+			return true;
+		} else if (board[0][1] == board[2][1] && board[0][1] != getSymbol() && board[0][1] != 0
+				&& board[1][1] == 0) {
+			nextMove = 5;
+			return true;
+		} else if (board[0][2] == board[2][2] && board[0][2] != getSymbol() && board[0][2] != 0
+				&& board[1][2] == 0) {
+			nextMove = 8;
+			return true;
+		} else if (board[0][0] == board[0][2] && board[0][0] != getSymbol() && board[0][0] != 0
+				&& board[0][1] == 0) {
+			nextMove = 4;
+			return true;
+		} else if (board[1][0] == board[1][2] && board[1][0] != getSymbol() && board[1][0] != 0
+				&& board[1][1] == 0) {
+			nextMove = 5;
+			return true;
+		} else if (board[2][0] == board[2][2] && board[2][0] != getSymbol() && board[2][0] != 0
+				&& board[2][1] == 0) {
+			nextMove = 6;
+			return true;
+		}
+		return false;
+	}
+
 	@Override
 	public int makeTurn() {
 		return nextMove;
diff --git a/Tic-Tac-Toe/src/main/TicTacToe.java b/Tic-Tac-Toe/src/main/TicTacToe.java
index a8fef69..e3ff091 100644
--- a/Tic-Tac-Toe/src/main/TicTacToe.java
+++ b/Tic-Tac-Toe/src/main/TicTacToe.java
@@ -7,7 +7,7 @@ public class TicTacToe {
 	Player turn;
 
 	private boolean running;
-	
+
 	public static final int MODE_NORMAL = 0;
 	public static final int MODE_AI = 1;
 
@@ -15,14 +15,14 @@ public class TicTacToe {
 
 		board = new Board();
 
-		switch(mode) {
+		switch (mode) {
 		case MODE_NORMAL:
-			player1 = new Player('X');
-			player2 = new Player('O');
+			player1 = new Player(Options.player1Symbol);
+			player2 = new Player(Options.player2Symbol);
 			break;
 		case MODE_AI:
-			player1 = new Player('X');
-			player2 = new PlayerAI('O');
+			player1 = new Player(Options.player1Symbol);
+			player2 = new PlayerAI(Options.player2Symbol);
 			break;
 		}
 		turn = player1;
@@ -37,7 +37,9 @@ public class TicTacToe {
 		board.draw();
 		turn.printTurnMessage();
 		if (turn instanceof PlayerAI) {
-			((PlayerAI)turn).calculateNextMove(board.getBoard());
+			if (!((PlayerAI) turn).calculateNextMove(board.getBoard())) {
+				System.exit(0);
+			}
 		}
 		int field = turn.makeTurn();
 		while (!board.isFieldFree(field)) {
@@ -48,9 +50,11 @@ public class TicTacToe {
 		board.place(field, turn.getSymbol());
 		char winner = board.testWinner();
 		if (winner > 1) {
+			Cmd.cls();
 			board.draw();
 			System.out.println(winner + " hat gewonnen!");
 		} else if (winner == 1) {
+			Cmd.cls();
 			board.draw();
 			System.out.println("Unetschieden!");
 		}
@@ -58,7 +62,7 @@ public class TicTacToe {
 			System.out.println("Noch eine Runde? [y/n]");
 			if (Input.yesNoDialog()) {
 				board.clear();
-			}else {
+			} else {
 				running = false;
 			}
 		}
@@ -67,6 +71,6 @@ public class TicTacToe {
 		} else {
 			turn = player1;
 		}
-
+		Cmd.cls();
 	}
 }