WPF Path 画箭头

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525" WindowStartupLocation="CenterScreen">
    <Grid Background="White">
        <Border Width="36" Height="36">
            <Path Fill="Red" Data="M -15,8 L 17,17 C 17,17 19,18 17,19 L 17,19 L -15,28 C -15,28 -17,28.2 -16,26 L -16,26 L -5,18 L -16,10 C -16,10 -17,8.5 -15,8 Z"></Path>
        </Border>
    </Grid>
</Window>