Public Class square
    Private size As Double  ' instance variable

    Public Property Length() As Double
        Get
            Return size
        End Get
        Set(ByVal Value As Double)
            If Value > 0 Then
                size = Value
            End If

        End Set
    End Property

    ' default constructor
    Public Sub New()
        size = 1
    End Sub

    'overlosding constructor
    Public Sub New(ByVal len As Double)
        If len <= 0 Then
            size = 1
        Else
            size = len
        End If

    End Sub

    ' area method
    Public Function calcArea()
        Dim area As Double
        area = size * size
        Return area
    End Function

    ' perimeter method
    Public Function calcPerimeter()
        Dim perimeter As Double
        perimeter = size * 4
        Return perimeter
    End Function
End Class