Сформировать новый квадратный массив, переставив 4 блока размера n*n первого массива - VB

Dim a() As Integer, b() As Integer
Form1.Cls
n = InputBox("n")
ReDim a(1 To 2 * n, 1 To 2 * n), b(1 To 2 * n, 1 To n * 2)
Randomize
For i = 1 To 2 * n
For j = 1 To 2 * n
 a(i, j) = Int(Rnd(1) * 10)
 Print a(i, j); vbTab;
Next j
Print
Next i
 
Print
 
For i = 1 To n
For j = 1 To n
 b(i, j) = a(i + n, j)
 b(i, j + n) = a(i, j)
 b(i + n, j + n) = a(i, j + n)
 b(i + n, j) = a(i + n, j + n)
Next j
Next i
 
For i = 1 To 2 * n
For j = 1 To 2 * n
 Print b(i, j); vbTab;
Next j
Print
Next i