codice:
Option Explicit
Private Type BlinkingPoint
    x As Single
    y As Single
    blinkOn As Boolean
End Type
Private Points() As BlinkingPoint

Private Sub Form_Load()
    Picture1.DrawWidth = 10
    Picture1.ForeColor = vbRed
    ReDim Points(0)
    Timer1.Enabled = False
End Sub

Private Sub Picture1_MouseDown(Button As Integer, Shift As Integer, x As Single, y As Single)
    Dim newPt As BlinkingPoint
    newPt.x = x
    newPt.y = y
    newPt.blinkOn = True
    Picture1.PSet (x, y), Picture1.ForeColor
    If Timer1.Enabled Then
        ReDim Preserve Points(UBound(Points) + 1)
    End If
    Points(UBound(Points)) = newPt
    Timer1.Enabled = True
End Sub

Private Sub Timer1_Timer()
    Dim counter As Long
    For counter = LBound(Points) To UBound(Points)
        Picture1.PSet (Points(counter).x, Points(counter).y), IIf(Points(counter).blinkOn, Picture1.BackColor, Picture1.ForeColor)
        Points(counter).blinkOn = Not Points(counter).blinkOn
    Next
End Sub