@pugzy, so yes, "the engine" is obviously meaning the graphical engine. You will be able to see this clearly, unless of course, you have the IQ of a baked vegetable. Either way, the sentence is not fail, as the underlying principles are correct.
Maybe not electricity but maybe there could be light entitys that you could place in other places EX: You set the time to 1:00 AM and you can spawn a light entity in a house which would briten it up. Good idea now?