Chronological development of ideas is often not logical. Often, I think we(teachers) show students a finished product which hides the struggle and toil from which the concept was wrought. Of course, it is good for new generations to fight new problems. But, I wonder, does it help to better understand the struggles which came before? I think yes. So, I try to embed history in my presentation when it is possible, or better yet, when it is interesting. Naturally, I will come here when vexed by various historical questions.