Wow, I have just seen the bit of film showing people kneeling, not in rows as in all the news footage over the past year, but in perfect circles around the Kaaba in Mecca. Gosh, how very beautiful.
Of course, it makes sense, all round (!) the world people line up in rows towards Mecca, so actually being right there means a circle. So bigger circles are created all the time, but in interrupted segments. Back to my A level Maths, each portion of a circle is meant to be a tiny straight line. Voila, in real life.