C# 8: extended pattern matching with the switch expression - property pattern, recursive pattern

Program.cs

static string M3(Shape shape)
  => shape switch
  {
    CombinedShape (var shape1, var (pos, _)) => $"combined shape - shape1: {shape1.Name}, pos of shape2: {pos}",
    { Size: (200, 200), Position: var pos } => $"shape with size 200x200 at position {pos.x}:{pos.y}",
    Ellipse (var pos, var size) => $"Ellipse with size {size} at position {pos}",
    Rectangle (_, var size) => $"Rectangle with size {size}",
    _ => "another shape"
  };