XAML Grid içerisine border ve hücre içerisine ikinci bir grid oluşturmak

XAML Grid içerisine border ve hücre içerisine ikinci bir grid oluşturmak

<Grid>

        <Grid.RowDefinitions>

            <RowDefinition Height="50"></RowDefinition>

            <RowDefinition></RowDefinition>

        </Grid.RowDefinitions>

        <Border Grid.Column="0" Grid.Row="0" Background="Cyan"/>

        <Border Grid.Row="1" Grid.Column="0" >

            <Grid>

                <Grid.ColumnDefinitions>

                    <ColumnDefinition></ColumnDefinition>

                    <ColumnDefinition Width="150"></ColumnDefinition>

                </Grid.ColumnDefinitions>

                <Border Grid.Row="0" Grid.Column="0"/>

                <Border Grid.Row="0" Grid.Column="1" Background="Cyan" >

                    <Grid>

                        <Grid.RowDefinitions>

                            <RowDefinition Height="50" ></RowDefinition>

                            <RowDefinition Height="50"></RowDefinition>

                            <RowDefinition Height="50"></RowDefinition>

                            <RowDefinition Height="50"></RowDefinition>

                            <RowDefinition Height="50"></RowDefinition>

                            <RowDefinition Height="50"></RowDefinition>

                           

                           

                        </Grid.RowDefinitions>

                        <Border Grid.Row="0" Grid.Column="0" Background="CadetBlue" BorderBrush="Black" BorderThickness="1,1,1,0"/>

                        <Border Grid.Row="1" Grid.Column="0" Background="CadetBlue" BorderBrush="Black" BorderThickness="1,1,1,0"/>

                        <Border Grid.Row="2" Grid.Column="0" Background="CadetBlue" BorderBrush="Black" BorderThickness="1,1,1,0"/>

                        <Border Grid.Row="3" Grid.Column="0" Background="CadetBlue" BorderBrush="Black" BorderThickness="1,1,1,0"/>

                        <Border Grid.Row="4" Grid.Column="0" Background="CadetBlue" BorderBrush="Black" BorderThickness="1,1,1,1"/>

                    </Grid>

                </Border>

            </Grid>

        </Border>

    </Grid>