If you resize the program, it clears, defines new corner points, and starts over. If you cover and expose the form, the program draws the same Sierpinski gasket.

Private LastX As Single
Private LastY As Single

Private CornerX(0 To 2) As Single
Private CornerY(0 To 2) As Single

' Draw the Sierpinski gasket.
Private Sub Form_Load()
Dim i As Integer

    Randomize
    Me.Show
    Do
        ' Pick the next corner.
        i = Int(Rnd * 3)

        ' Move halfway from the current point
        ' to the new corner.
        LastX = (LastX + CornerX(i)) / 2
        LastY = (LastY + CornerY(i)) / 2
        Me.PSet (LastX, LastY)

        ' Check for events.
        DoEvents
    Loop
End Sub

' Define the corner points.
Private Sub Form_Resize()
Const R As Single = 60
Dim i As Integer

    ' Clear.
    Me.Cls

    ' Define the corners.
    CornerX(0) = R + 10
    CornerY(0) = Me.ScaleHeight - R - 10
    CornerX(1) = Me.ScaleWidth / 2
    CornerY(1) = R + 10
    CornerX(2) = Me.ScaleWidth - R - 10
    CornerY(2) = Me.ScaleHeight - R - 10

    ' Draw the corners.
    For i = 0 To 2
        Me.Circle (CornerX(i), CornerY(i)), R
    Next i

    ' Pick a starting point.
    i = Int(Rnd * 3)
    LastX = CornerX(i)
    LastY = CornerY(i)
End Sub

Private Sub Form_Unload(Cancel As Integer)
    End
End Sub