Check this one.
Public Shared Sub pattern()
Dim n As Integer = 3
For i As Integer = 0 To n - 1
For k As Integer = 0 To i - 1
Console.Write("*")
Next
Console.WriteLine()
Next
For i As Integer = n To 1 Step -1
For k As Integer = i To 1 Step -1
Console.Write("*")
Next
Console.WriteLine()
Next
End Sub