Answers will vary from person to person. For many, it is triangular--in the same category as great stories and traditions. For others it is rectangular--a tedious list of things to do. For still others, it is circular--conjuring up thoughts of pain, betrayal and distrust. But how many people think of Christianity as square--as something historically factual and reality altering? Not many. I would say that even the majority of Christians do not think of squares when they think of Christianity, Jesus, and the Bible. I think that is a foundational issue that needs to be addressed within the Church today. The shape you think of when you think about Christianity will ultimately shape (pun definitely intended) your entire worldview.
I think that one of the ways the Holy Spirit uses apologetics is in reshaping the way we think of Christianity. For much of my life, the shape of Christianity oscillated back and forth between rectangular and triangular--from tradition to duty and back again. However, as I began to study apologetics, the shape gradually morphed to becoming more square. Before I go on, I can already anticipate some people's reaction. They might say, "That is just the problem with you apologetics type people. You make everything all about the cold, hard facts. You have no heart!" That is not what I am saying. I think that when you see Christianity as a historical, reality altering fact, you are more able to enjoy the traditions, engage in duties, and cope with the hurt. In that sense, you might say that there is room for all of the shapes in a square, as long as they are put into the proper perspective. For instance, two right triangles or two rectangles can make a square. Even a circle can fit inside of a square, if the square is only big enough to hold it.
Someone might say, "Your analogy is all screwed up. You could fit a bunch of little squares into a rectangle. You could fit a circle into a triangle and a rectangle. And you could also make a rectangle with two right triangles." Obviously that is pressing the analogy too hard. But just for fun, I actually think I can make it work in favor of my point. Now remember, all of these shapes are in our mind--they have to do with the way we think of things. Therefore, it only makes sense to think that the size of a shape relates to it's importance. If that makes sense, then I think my analogy holds together. For instance, you cannot fit a square into a rectangle unless it the square is smaller. That means we would have to consider the historical, reality altering facts less important than your list of chores, duties etc. Granted, we almost certainly think of our chores more often, but I doubt any of us would say that the events of 9/11 are less important than my taking out the garbage. That is nonsense. Furthermore, it doesn't make any sense to put circles (pain and hurt) into triangles (fond memories and traditions). Maybe circles (pain/hurt) could be put into rectangles (duties/obligations), but once again, that would ultimately mean that the circle (pain/hurt) is less important than the rectangle (duties/obligations), and that just generally isn't the case. The only way it works is for every shape to be in it's proper perspective. As it turns out, it only makes sense for the square to be the biggest (most important) shape, and when it is, then the rest of the shapes are put into proper perspective. What is more, when we realize that Christianity is a square--a historical, reality altering truth --we realize that it is of such great importance (so big) that it can hold all other squares (facts of history) as well. And it does.