Task: Langton's ant
Java: import java.awt.Color;
import java.awt.Graphics;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Langton extends JFrame{
	private JPanel planePanel;
	private static final int ZOOM = 4;
	
	public Langton(final boolean[][] plane){
		planePanel = new JPanel(){
			@Override
			public void paint(Graphics g) {
				for(int y = 0; y < plane.length;y++){
					for(int x = 0; x < plane[0].length;x++){
						g.setColor(plane[y][x] ? Color.BLACK : Color.WHITE);
						g.fillRect(x * ZOOM, y * ZOOM, ZOOM, ZOOM);
					}
				}
				
				g.setColor(Color.GREEN);
				g.fillRect(plane[0].length / 2 * ZOOM,
				           plane.length / 2 * ZOOM, ZOOM/2, ZOOM/2);
			}
		};
		planePanel.setSize(plane[0].length - 1, plane.length - 1);
		add(planePanel);
		setSize(ZOOM * plane[0].length, ZOOM * plane.length + 30);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
	}
	
	public static void main(String[] args){
		new Langton(runAnt(100, 100));
	}

	private static boolean[][] runAnt(int height, int width){
		boolean[][] plane = new boolean[height][width];
		int antX = width/2, antY = height/2;
		int xChange = 0, yChange = -1; 
		while(antX < width && antY < height && antX >= 0 && antY >= 0){
			if(plane[antY][antX]){
				
				if(xChange == 0){ 
					xChange = yChange;
					yChange = 0;
				}else{ 
					yChange = -xChange;
					xChange = 0;
				}
			}else{
				
				if(xChange == 0){ 
					xChange = -yChange;
					yChange = 0;
				}else{ 
					yChange = xChange;
					xChange = 0;
				}
			}
			plane[antY][antX] = !plane[antY][antX];
			antX += xChange;
			antY += yChange;
		}
		return plane;
	}
}

VB: Option Explicit

Sub Ant()
  Dim TablDatas(1 To 200, 1 To 256) As String, sDir As String, sFile As String, Str As String
  Dim ColA As Integer, LigA As Long, ColF As Integer, LigF As Long, i As Long, j As Integer, Num As Long
  Dim Top As Boolean, Left As Boolean, Bottom As Boolean, Right As Boolean
    
    
    Select Case Int(Rnd(4) * 4)
      Case 0: Top = True
      Case 1: Right = True
      Case 2: Bottom = True
      Case 3: Left = True
    End Select
      
    LigF = 80
    ColF = 50
    For i = 1 To 200
        For j = 1 To 256
            TablDatas(i, j) = " "
        Next
    Next
    
    sDir = "/Users/mjreed/Desktop/"
    
    sFile = "Langton_Ant.txt"
    
    
    Dim Dir As String
    For i = 1 To 15000
        LigA = LigF
        ColA = ColF
       
        If LigA = 1 Or ColA = 1 Or ColA = 256 Or LigA = 200 Then GoTo Fin
        If TablDatas(LigA, ColA) = " " Then
            TablDatas(LigA, ColA) = "#"
            Select Case True
                Case Top: Top = False: Right = True: LigF = LigA: ColF = ColA + 1
                Case Left: Left = False: Top = True: LigF = LigA - 1: ColF = ColA
                Case Bottom: Bottom = False: Left = True: LigF = LigA: ColF = ColA - 1
                Case Right: Right = False: Bottom = True: LigF = LigA + 1: ColF = ColA
            End Select
        Else
            TablDatas(LigA, ColA) = " "
            Select Case True
                Case Top: Top = False: Left = True: LigF = LigA: ColF = ColA - 1
                Case Left: Left = False: Bottom = True: LigF = LigA + 1: ColF = ColA
                Case Bottom: Bottom = False: Right = True: LigF = LigA: ColF = ColA + 1
                Case Right: Right = False: Top = True: LigF = LigA - 1: ColF = ColA
            End Select
        End If
    Next i
Fin:
    
    Num = FreeFile
    Open sDir & sFile For Output As #Num
    
    For i = 1 To UBound(TablDatas, 1)
        Str = vbNullString
        For j = 1 To UBound(TablDatas, 2)
            Str = Str & TablDatas(i, j)
        Next j
        Print #Num, Str
    Next i
    Close #Num
    Exit Sub
End Sub