C#

<Window x:Class="Styles.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="150" Width="525">
    <Window.Resources>
<Style x:Key="Poly1" TargetType="{x:Type Button}">
        	<Setter Property="Template">
        		<Setter.Value>
        			<ControlTemplate TargetType="{x:Type Button}">
        				<Grid>
                            <Polygon Fill="{TemplateBinding Background}"  Points="10,10 80,10 120,45 80,75 10,75 45,45" Stroke="{TemplateBinding BorderBrush}" StrokeThickness="2"/>
        					<ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
        				</Grid>
        				<ControlTemplate.Triggers>
        					<Trigger Property="IsFocused" Value="True"/>
        					<Trigger Property="IsDefaulted" Value="True"/>
        					<Trigger Property="IsMouseOver" Value="True"/>
        					<Trigger Property="IsPressed" Value="True"/>
        					<Trigger Property="IsEnabled" Value="False"/>
        				</ControlTemplate.Triggers>
        			</ControlTemplate>
        		</Setter.Value>
        	</Setter>
        </Style>
</Window.Resources>
<WrapPanel>
        <Button Style="{DynamicResource Poly1}"></Button>
        <Button Style="{DynamicResource Poly1}"></Button>
 </WrapPanel>
</Window>