Program Writing in Visual Basic

I am having trouble creating a program in Visual Basic that prints the * in a diamond shape.  Do you have any suggestions?

This is what I have so far.  It is an un-proportioned diamond, I need a normal diamond.  What am I doing wrong?


Dim i As Integer
        Dim y As Integer
        Dim j As Integer

        For i = -9 To 9
            y = System.Math.Abs(i)
            y = (y * (-1)) + 10

            Console.WriteLine("")
            For j = 1 To y
                Console.Write("*")
            Next

            i += 1
        Next



Any help is greatly appreciated.