Inverted-angle radius in WPF (something like a negative radius)

Question

I am trying to create a border with a negative angular radius, for example:

I want a radius inside. Is this possible when building functions, or do I need to draw it using a path?

Answer 1

You can use Border in Border

 <Border Background="Black"> <Border Margin="10" Background="White" CornerRadius="20"> <!-- ... --> </Border> </Border>