Upgrading Façades

There’s no rule in the Façade pattern that says you can only have a single type of façade, which means you may find yourself in situations where an abstract base class comes in handy. While this isn’t something new or revolutionary for you object-oriented folks, you could have a Façade class like the one in the following code that all other façades must implement:

public abstract class AbstractFacade : MonoBehaviour
{
    public abstract IEnumerator Save(double score);
}

Then you could derive concrete subclasses any way you like – for example, different auto-save façades dealing with cloud and disk storage, as seen in the following snippet:

public class CloudStorageFacade : AbstractFacade
{
    public override IEnumerator Save(double score)
    {
        yield break;
    }
}
public class LocalStorageFacade : AbstractFacade
{
    public override IEnumerator Save(double score)
    {
        yield break...