Two dimensional array as buffer for screen VB.Net Exercise - Visual Basic Programming Course

Imports System
Public Class exercise92
    Public Shared Sub Main()
        Dim position As Char(,) = New Char(19, 69) {}
        Dim generator As Random = New Random()
        Dim i As Integer = 0

        While i < 80
            position(generator.[Next](0, 20), generator.[Next](0, 70)) = "X"c
            i += 1
        End While

        For i = 0 To 20 - 1

            For j As Integer = 0 To 70 - 1
                Console.Write(position(i, j))
            Next

            Console.WriteLine()
        Next
    End Sub
End Class