With this app, it's possible to add rectangular shapes to each cell.



<phone:PhoneApplicationPage
    x:Class="BasicLayout02.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Pho
ne"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    shell:SystemTray.IsVisible="True">

    <!--LayoutRoot is the root grid where all page content is placed-->
    <Grid x:Name="LayoutRoot" Background="Transparent">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>



        <!--TitlePanel contains the name of the application and page title-->
        <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28">
            <TextBlock Text="Colorful Cells" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}" HorizontalAlignment="Center"/>
        </StackPanel>

        <!--ContentPanel - place additional content here-->
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
            <Grid.RowDefinitions>
                <RowDefinition Height="*" />
                <RowDefinition Height="*" />
                <RowDefinition Height="*" />
                <RowDefinition Height="*" />
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition />
                <ColumnDefinition />
                <ColumnDefinition  Width="114" />
                <ColumnDefinition />
            </Grid.ColumnDefinitions>

            <TextBlock>1</TextBlock>
            <TextBlock Grid.Column="1">2</TextBlock>
            <TextBlock Grid.Column="2">3</TextBlock>
            <TextBlock Grid.Column="3">4</TextBlock>

            <TextBlock Grid.Row="1">5</TextBlock>
            <TextBlock Grid.Row="1" Grid.Column="1">6</TextBlock>
            <TextBlock Grid.Row="1" Grid.Column="2">7</TextBlock>
            <TextBlock Grid.Row="1" Grid.Column="3">8</TextBlock>

            <TextBlock Grid.Row="2">9</TextBlock>
            <TextBlock Grid.Row="2" Grid.Column="1">10</TextBlock>
            <TextBlock Grid.Row="2" Grid.Column="2">11</TextBlock>
            <TextBlock Grid.Row="2" Grid.Column="3">12</TextBlock>

            <TextBlock Grid.Row="3">13</TextBlock>
            <TextBlock Grid.Row="3" Grid.Column="1">14</TextBlock>
            <TextBlock Grid.Row="3" Grid.Column="2">15</TextBlock>
            <TextBlock Grid.Row="3" Grid.Column="3">16</TextBlock>

            <Rectangle  Grid.Row="0" Grid.Column="0" Width="23" Fill="White"></Rectangle>
            <Rectangle  Grid.Row="0" Grid.Column="1" Width="23" Fill="Yellow"></Rectangle>
            <Rectangle  Grid.Row="0" Grid.Column="2" Width="23" Fill="Red"></Rectangle>
            <Rectangle  Grid.Row="0" Grid.Column="3" Width="23" Fill="Blue"></Rectangle>

            <Rectangle  Grid.Row="1" Grid.Column="0" Width="23" Fill="Yellow"></Rectangle>
            <Rectangle  Grid.Row="1" Grid.Column="1" Width="23" Fill="Red"></Rectangle>
            <Rectangle  Grid.Row="1" Grid.Column="2" Width="23" Fill="Blue"></Rectangle>
            <Rectangle  Grid.Row="1" Grid.Column="3" Width="23" Fill="White"></Rectangle>

            <Rectangle  Grid.Row="2" Grid.Column="0" Width="23" Fill="Red"></Rectangle>
            <Rectangle  Grid.Row="2" Grid.Column="1" Width="23" Fill="Blue"></Rectangle>
            <Rectangle  Grid.Row="2" Grid.Column="2" Width="23" Fill="White"></Rectangle>
            <Rectangle  Grid.Row="2" Grid.Column="3" Width="23" Fill="Yellow"></Rectangle>

            <Rectangle  Grid.Row="3" Grid.Column="0" Width="23" Fill="Blue"></Rectangle>
            <Rectangle  Grid.Row="3" Grid.Column="1" Width="23" Fill="White"></Rectangle>
            <Rectangle  Grid.Row="3" Grid.Column="2" Width="23" Fill="Yellow"></Rectangle>
            <Rectangle  Grid.Row="3" Grid.Column="3" Width="23" Fill="Red"></Rectangle>



        </Grid>

    </Grid>
</phone:PhoneApplicationPage>