diff --git a/src/main/java/dotsandboxes/DotsAndBoxesGrid.java b/src/main/java/dotsandboxes/DotsAndBoxesGrid.java
index 4f774b198f230ca82e5cc94d51967846aa05d5f5..ec065ccc313b047bfbd8e141217fb09e38115ee7 100644
--- a/src/main/java/dotsandboxes/DotsAndBoxesGrid.java
+++ b/src/main/java/dotsandboxes/DotsAndBoxesGrid.java
@@ -107,13 +107,14 @@ public class DotsAndBoxesGrid {
      * @return true if all four sides have been drawn.
      */
     public boolean boxComplete(int x, int y) {
-        if (x >= width - 1 || x < 0 || y >= height - 1 || y < 0) {
-            return false;
+        if (horizontals[x][y] && verticals[x][y] && horizontals[x+1][y] && verticals[x][y+1]) {
+
+        //if (x >= width - 1 || x < 0 || y >= height - 1 || y < 0) {
+            return true;
         }
 
         // A box is complete if the north and south horizontals and the east and west verticals have all been drawn.
-        // FIXME: You'll need to fix this code (after writing a test first).
-        return true;
+        return false;
     }
 
     /** Tries to claim a box for a player. If the box is complete, sets the ownership and returns true. */
@@ -139,8 +140,9 @@ public class DotsAndBoxesGrid {
         if (y >= height || y < 0) {
             throw new IndexOutOfBoundsException(String.format("y was %d, which is out of range. Range is 0 to %d", y, height));
         }
-
-        // FIXME: You need to throw an exception if the line was already drawn.
+        if (horizontals[x][y]){
+            throw new IllegalStateException(String.format("You cannot draw a line here.  There is already a line."));
+        }
 
         this.horizontals[x][y] = true;
 
@@ -171,6 +173,9 @@ public class DotsAndBoxesGrid {
             throw new IndexOutOfBoundsException(String.format("y was %d, which is out of range. Range is 0 to %d", y, height - 1));
         }
 
+        if (verticals[x][y]){
+            throw new IllegalStateException(String.format("You cannot draw a line here.  There is already a line."));
+        }
         // You need to throw an exception if the line was already drawn.
 
         this.verticals[x][y] = true;