diff --git a/cs621/proj4/KnightsTour.java b/cs621/proj4/KnightsTour.java
index b6f1d76..cb9ffdd 100644
--- a/cs621/proj4/KnightsTour.java
+++ b/cs621/proj4/KnightsTour.java
@@ -67,6 +67,9 @@ public class KnightsTour extends JFrame
                         setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
                         add(m_startButton = new JButton("Start Knight's Tour"));
                         m_startButton.addActionListener(m_handler);
+                        add(new Box.Filler(new Dimension(0, 4),
+                                           new Dimension(0, 4),
+                                           new Dimension(0, 4)));
                         add(m_statusLabel = new JLabel());
                     }});
                 }});
@@ -90,10 +93,10 @@ public class KnightsTour extends JFrame
         m_boardPanel.setBorder(BorderFactory.createEmptyBorder(5, 0, 0, 0));
         for (int x = 0; x < width; x++)
         {
-            for (int y = 0; y < width; y++)
+            for (int y = 0; y < height; y++)
             {
                 JLabel l = new JLabel(m_ktBoard.getStepAt(x, y) == 0
-                        ? "h"
+                        ? ""
                         : new Integer(m_ktBoard.getStepAt(x, y)).toString(),
                     SwingConstants.CENTER);
                 l.setBorder(BorderFactory.createBevelBorder(BevelBorder.LOWERED));
@@ -117,6 +120,42 @@ public class KnightsTour extends JFrame
             if (e.getSource() == m_startButton)
             {
                 m_statusLabel.setText("Running...");
+
+                /* first validate input text fields */
+                int width, height, startx, starty;
+                try
+                {
+                    width = Integer.parseInt(m_widthField.getText());
+                    height = Integer.parseInt(m_heightField.getText());
+                    startx = Integer.parseInt(m_startXField.getText());
+                    starty = Integer.parseInt(m_startYField.getText());
+                }
+                catch (NumberFormatException nfe)
+                {
+                    m_statusLabel.setText("Non-numerical input!");
+                    return;
+                }
+                if (width < 1 || height < 1 || startx < 0 || starty < 0 ||
+                        startx >= width || starty >= height)
+                {
+                    m_statusLabel.setText("Invalid input!");
+                    return;
+                }
+
+                /* create a new KnightsTourBoard object */
+                m_ktBoard = new KnightsTourBoard(width, height);
+                createBoardPanel();
+
+                /* run the tour and update GUI */
+                if (m_ktBoard.tour(startx, starty))
+                {
+                    createBoardPanel();
+                    m_statusLabel.setText("Finished.");
+                }
+                else
+                {
+                    m_statusLabel.setText("Solution not found!");
+                }
             }
         }
     }