Mirror multiple cells in different sheets

I'm trying to create code that mirrors specified cells in different sheets of the same Excel document. For example, I enter something in A1 in one sheet, I want it to be automatically entered at D6 in another sheet, and vice versa. This is the code I've been trying to adapt for my purposes:

In Sheet1 and Sheet2 modules:

Private Sub Worksheet_Change(ByVal Target As Range)
    If Cells_Mirrored(Target) Then
        'cells were mirrored
    End If
End Sub

In a standard module:

Option Explicit

Function Cells_Mirrored(rTarget As Range) As Boolean
    Dim aFrom()
    Dim aTo()
    Dim sh1 As Worksheet
    Dim sh2 As Worksheet
    Dim rFrom As Range
    Dim rTo As Range
    Dim sFrom as String
    Dim sTo as String

    Dim a1()
    Dim a2()
    Dim i As Integer

    If rTarget.Count = 1 Then
        '*************************************
        'Set these variables to what you need
        Set sh1 = Worksheets("Sheet 1")
        Set sh2 = Worksheets("Sheet 2")

        With sh1
            ReDim a1(1 To 4)
            a1(1) = .Range("A1:A20")
            a1(2) = .Range("A1")
            a1(3) = .Range("B2")
            a1(4) = .Range("D3")
        End With

        With sh2
            ReDim a2(1 To 4)
            a2(1) = .Range("B10:B30")
            a2(2) = .Range("E4")
            a2(3) = .Range("F5")
            a2(4) = .Range("G6")
        End With
        '*************************************

        If rTarget.Worksheet.Name = sh1.Name Then
            aFrom() = a1()
            aTo() = a2()
        ElseIf rTarget.Worksheet.Name = sh2.Name Then
            aFrom() = a2()
            aTo() = a1()
        Else
            GoTo EF
        End If

        Application.EnableEvents = False
        'Include next line Just in Case something happens
        '    You don't want to leave EnableEvents off
        On Error Resume Next
        For i = LBound(aFrom()) To UBound(aFrom())
            Set rFrom = aFrom(i)
            If Not Intersect(rTarget, rFrom) Is Nothing Then
                Cells_Mirrored = True

                Set rTo = aTo(i)

                sFrom = rFrom.Worksheet.Name & "!" & rFrom.Address
                sTo = rTo.Worksheet.Name & "!" & rTo.Address

                If True Then
                    'This is here for debugging
                    '    just change to "If False Then" when satisfied it works
                    Debug.Print sFrom; Spc(1); sTo
                    Stop
                End If

                Err.Clear
                rFrom.Copy rTo
                If Err.Number <> 0 Then
                    MsgBox sFrom & " was not mirrored in " & sTo
                End If
            End If
        Next i
        Application.EnableEvents = True
    End If
EF:
End Function

This code is adapted from others - the code runs but doesn't mirror cells as intended. My programming aptitude modest at best so it's likely there is something very simple that I'm missing. Any help is appreciated!

Cheers,

Andrew