First, there is a bug that I did not address in the last episode.  The character gets
killed if you ride a lift going down.  So, we'll just add this quick check in place

                    For Each MobileWall In MobileWalls
                        If PlayerLoc.IntersectsWith(MobileWall.Loc) AndAlso MobileWalls.IndexOf(MobileWall) <> R Then
                            IsGoner = True
                            'The player has been smushed.  Lose a life.
                            PlayerVeloc = SBARINITIALVELOCITY
                        End If
                    MobileWall = DirectCast(MobileWalls(R), MovingWall)
Now that we have our moving walls fully functional, it's time to get them into the file. Getting them into the file is not much of a problem. The real problem is going to come when we try to create a moving wall object with the editor, since it consists of two rectangles and two more integers. But, first, let's knock out the SaveLevel routine for MovingWalls. There are 10 properties that need to be saved.
            'Moving walls written to file.
            For Each MobileWall In MobileWalls
It's important that the arguments be supplied in the order that they go into the constructor. It'll save you some time. Now, update all of your files so that each will have the number of moving walls written into it in the right place. (even 0 needs to be written) Now, to read a file that has MobileWall data in it, we read each number back from the file into our MobileWall structures one by one.
        MobileWalls = New ArrayList(BR.ReadInt32)
        For LV = 1 To MobileWalls.Capacity
            MobileWalls.Add(New MovingWall(Rectangle.FromLTRB(BR.ReadInt32(), BR.ReadInt32(), BR.ReadInt32(), BR.ReadInt32()), _
            BR.ReadInt32(), BR.ReadInt32(), _
            Rectangle.FromLTRB(BR.ReadInt32(), BR.ReadInt32(), BR.ReadInt32(), BR.ReadInt32())))
            'Moving wall data from file.
Don't forget to remove the arraylist instantiation that occurs in Form_Load. Now that we've got that out of the way, let's work on the editor.
To take two rectangles, we should clearly take two selection rectangles, because it would be really hard for the editor (possibly you) to make a decent rectangle with four number prompts. The dX and dY properties can be handled by a number prompt, by the way, similar to the one we did for Jumpboard. Now, the question is how do we keep up with two selection rectangles? An answer: these selection rectangles will be made one at a time... after we make one, we'll hold it in memory until the second one is made. From there, we'll make our movingwall from the two selection rectangles. For even more ease of use, we can automatically set it so that the larger rectangle will become the boundary and the smaller will become the moving wall. Now, let's get to it. Our editor key for Moving Walls can be M, so we add support for the key in the KeyDown event.
        ElseIf e.KeyCode = Keys.M Then
            If Not IsMouseDown Then
                MDObject = "M"c
            End If
Now, we go into the MouseUp event and from there, we should be able to coordinate the two selection rectangle.
            Case "M"c
                If MemoryRect.IsEmpty Then
                    MemoryRect = Placed
                    Dim Mw As MovingWall  'Will hold the data that we are about to collect.
                    Clock.Enabled = False
                    'Stop timed execution.
                    If Placed.Width > MemoryRect.Width Then
                        'Placed is bigger, therefore it must be the boundary.
                        Mw.Boundary = Placed
                        Mw.Loc = MemoryRect
                        'Placed is smaller, it must be the actual wall.
                        Mw.Boundary = MemoryRect
                        Mw.Loc = Placed
                    End If
                    Mw.dX = NumericBox.Show(-24, 24, "X Velocity")
                    Mw.dY = NumericBox.Show(-24, 24, "Y Velocity")
                    'Set the wall velocity.
                    MobileWalls.Insert(0, Mw)
                    'Add it to our list of moving wall.
                    Clock.Enabled = True
                    'continue timed execution.
                End If
That wasn't too hard. I even was shocked to see that the trackbars handled the negatives nicely. Have fun.