Mine

Private Sub Go(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim width As Integer 
Dim lastRow, lastCol As Integer

        width = txtIn.Text

        Dim outputArray(width, width) As Integer

        Dim x, y As Integer

        For i = 1 To width
            For j = 1 To width
                outputArray(i, j) = 0
            Next
        Next

        x = Int(width/2) + 1
        y = 1

        outputArray(x, y) = 1

        

        For number = 2 To width ^ 2

            lastRow = x
            lastCol = y

            If x = width Then
                x = 1
            Else
                x += 1
            End If

            If y = 1 Then
                y = width
            Else
                y -= 1
            End If

            If outputArray(x, y) = 0 Then
                outputArray(x, y) = number
            Else
                If lastCol = width Then
                    y = 1
                    outputArray(lastRow, y) = number
                    x = lastRow
                Else
                    y = lastCol + 1
                    x = lastRow
                    outputArray(lastRow, y) = number
                End If
                
            End If
        Next

        Dim s As String

        For countrow = 1 To width
            s += vbCrLf
            For countcol = 1 To width
                s += CStr(outputArray(countcol, countrow)) + vbTab
            Next
        Next

        txtOut.Text = s
    End Sub