AbolishSnippet10.cs

var shapes = new Dictionary<string, object>
{
    { "FirstShape", new Rectangle(1, 1) },
    { "SecondShape", new Circle(6) }
};

foreach(var shape in shapes)
{
    if (shape.Value is Rectangle)
    {
        var height = ((Rectangle)shape.Value).Height;
        Console.WriteLine(height);
    }
    else if (shape.Value is Circle)
    {
        var height = ((Circle)shape.Value).Radius * 2;
        Console.WriteLine(height);
    }
}