C# 8 switch expression

Program.cs

static string M2(Shape shape)
  => shape switch
  {
    Shape s when s.Size.height > 100 => $"large shape with size {s.Size} at position {s.Position}",
    Ellipse e => $"Ellipse with size {e.Size} at position {e.Position}",
    Rectangle r => $"Rectangle with size {r.Size} at position {r.Position}",
    _ => "another shape"
  };