Программа, которая заполняет массив по спирали - VB

Public Sub Spirale()
Dim n As Integer, m As Integer
n = Application.InputBox("X")
m = Application.InputBox("Y")
l = 1
i1 = 1
j1 = 1
Do While (i1 <= n) And (j1 <= m)
For j = j1 To m
Cells(i1, j) = l
l = l + 1
Next j
If i1 < n Then
For i = i1 + 1 To n
Cells(i, m) = l
l = l + 1
Next i
End If
If j1 < m Then
For j = m - 1 To j1 Step -1
Cells(n, j) = l
l = l + 1
Next j
End If
If n - i1 > 1 Then
For i = n - 1 To i1 + 1 Step -1
Cells(i, j1) = l
l = l + 1
Next i
End If
i1 = i1 + 1
j1 = j1 + 1
n = n - 1
m = m - 1
Loop
End Sub