XAML:

<Window x:Class="MiscSamples.KanBanSample"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="KanBanSample" Height="670" Width="1225">
    <Window.Resources>
        <DataTemplate x:Key="InnerTemplate">
            <Grid Margin="10" MaxHeight="100" MaxWidth="100">
                <Path Data="M0.5,1 L1,68.5 56.25,68.25 68,55.5 68,0.5 z M56.375,68.281 L57.75,57.75 M68.25,55.25 L57.405993,58.203003"
                      Fill="#FFF4F4F5" Stroke="#3C5B8A" Stretch="Uniform"/>

                <TextBlock Text="{Binding DisplayName}"
                           FontSize="20" VerticalAlignment="Center" HorizontalAlignment="Center"/>
            </Grid>
        </DataTemplate>

        <DataTemplate x:Key="OuterTemplate">
            <Grid Margin="2" MaxWidth="300">
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto" SharedSizeGroup="Header"/>
                    <RowDefinition/>
                </Grid.RowDefinitions>

                <Border BorderThickness="1" BorderBrush="#6388B4">
                    <Border.Background>
                        <LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
                            <GradientStop Color="#88D1FF" Offset="0"/>
                            <GradientStop Color="#88D1FF" Offset=".1"/>
                            <GradientStop Color="#4586D6" Offset="1"/>
                        </LinearGradientBrush>
                    </Border.Background>

                    <TextBlock Text="{Binding DisplayName}"
                               FontSize="20" Foreground="White" Margin="10" TextWrapping="Wrap"
                               TextAlignment="Center"/>
                </Border>

                <Border BorderBrush="#6B86A4" BorderThickness="1" Background="#CDD3E1" Grid.Row="1" Margin="0,5,0,0">
                    <ItemsControl ItemsSource="{Binding Items}" Margin="10"
                                  ItemTemplate="{StaticResource InnerTemplate}">
                        <ItemsControl.ItemsPanel>
                            <ItemsPanelTemplate>
                                <WrapPanel/>
                            </ItemsPanelTemplate>
                        </ItemsControl.ItemsPanel>
                    </ItemsControl>
                </Border>

            </Grid>
        </DataTemplate>
    </Window.Resources>

    <ItemsControl ItemsSource="{Binding}" ItemTemplate="{StaticResource OuterTemplate}"
                  Grid.IsSharedSizeScope="True">
        <ItemsControl.ItemsPanel>
            <ItemsPanelTemplate>
                <VirtualizingStackPanel Orientation="Horizontal"/>
            </ItemsPanelTemplate>
        </ItemsControl.ItemsPanel>
    </ItemsControl>
</Window>

Code Behind:

 public partial class KanBanSample : Window
    {
        public KanBanSample()
        {
            InitializeComponent();

            DataContext = new List<KanBanSampleOuterItem>
                {
                    new KanBanSampleOuterItem()
                        {
                            DisplayName = "PETICION DE TAREAS",
                            Items =
                                {
                                    new KanBanSampleInnerItem("M"),
                                    new KanBanSampleInnerItem("N"),
                                }
                        },
                    new KanBanSampleOuterItem()
                        {
                            DisplayName = "SELECCION DE TAREAS (5)",
                            Items =
                                {
                                    new KanBanSampleInnerItem("H"),
                                    new KanBanSampleInnerItem("I"),
                                    new KanBanSampleInnerItem("J"),
                                    new KanBanSampleInnerItem("K"),
                                    new KanBanSampleInnerItem("L"),
                                }
                        },
                    new KanBanSampleOuterItem()
                        {
                            DisplayName = "DESARROLLO (4)",
                            Items =
                                {
                                    new KanBanSampleInnerItem("D"),
                                    new KanBanSampleInnerItem("E"),
                                    new KanBanSampleInnerItem("F"),
                                    new KanBanSampleInnerItem("G"),
                                }
                        },
                    new KanBanSampleOuterItem()
                        {
                            DisplayName = "PRUEBA (1)",
                            Items =
                                {
                                    new KanBanSampleInnerItem("C"),
                                }
                        },
                    new KanBanSampleOuterItem()
                        {
                            DisplayName = "TERMINADO",
                            Items =
                                {
                                    new KanBanSampleInnerItem("A"),
                                    new KanBanSampleInnerItem("B"),
                                }
                        }

                };
        }
    }

    public class KanBanSampleOuterItem
    {
        public string DisplayName { get; set; }

        public List<KanBanSampleInnerItem> Items { get; set; }

        public KanBanSampleOuterItem()
        {
            Items = new List<KanBanSampleInnerItem>();
        }
    }

    public class KanBanSampleInnerItem
    {
        public KanBanSampleInnerItem(string displayName)
        {
            DisplayName = displayName;
        }

        public string DisplayName { get; set; }
    }