Heres some quick and nast code i've put together - if it doesn't exactly do what you meant then it might at least go close...



Code:
Private Sub Command1_Click()
    Dim TempStr As String
    Dim i As Integer
    Dim myArray() As String

    'Get the string from the textarea (textbox)
    TempStr = Text1.Text

    'Create MyArray by delimiter cariiage return line feed
    myArray = Split(TempStr, vbCrLf)

    'Num elements in the new array
    Dim NumberOfElements As Integer
    NumberOfElements = UBound(myArray) + 1

    If NumberOfElements < 4 Then
        
        'Not enough lines entered in textbox
        ReDim Preserve myArray(3) 'extend array to 4 elements (0 to 3)
        For i = NumberOfElements To 3
            myArray(i) = "" 'initialise to 0-length string the new elements
        Next i
    
    ElseIf NumberOfElements > 4 Then
        
        'too many lines entered in textbox
        For i = 4 To UBound(myArray)
            'Add all the extral lines to the 4th line
            myArray(3) = myArray(3) & " " & myArray(i)
        Next i
        ReDim Preserve myArray(3) 'Reduce the array back to 4 elements
    
    End If

    'Put the string back together
    TempStr = myArray(0) & vbCrLf & _
    myArray(1) & vbCrLf & _
    myArray(2) & vbCrLf & _
    myArray(3)

    'Reassign it to the textbox
    Text1.Text = TempStr

End Sub