Time for action – bouncing off the walls

1. 1. Add the BuildBoundingBox() method to the Walls region of the Maze class as follows:

   private BoundingBox BuildBoundingBox(
       int x, 
       int z, 
       int point1, 
       int point2)
   {
       BoundingBox thisBox = new BoundingBox(
           wallPoints[point1], 
           wallPoints[point2]);
       thisBox.Min.X += x;
       thisBox.Min.Z += z;
       thisBox.Max.X += x;
       thisBox.Max.Z += z;
   
       thisBox.Min.X -= 0.1f;
       thisBox.Min.Z -= 0.1f;
       thisBox.Max.X += 0.1f;
       thisBox.Max.Z += 0.1f;
   
       return thisBox;
   }

2. 2. Add the GetBoundsForCell() method to the Walls region of the Maze class:

   public List<BoundingBox> GetBoundsForCell(int x, int z)
   {
       List<BoundingBox> boxes = new List<BoundingBox>();
   
       if (MazeCells[x, z].Walls[0])
           boxes.Add(BuildBoundingBox(x, z, 2, 4));
   
       if (MazeCells[x, z].Walls[1])
           boxes.Add(BuildBoundingBox(x, z, 6, 5));
   
       if (MazeCells[x, z].Walls[2])
           boxes.Add(BuildBoundingBox(x, z...