Forming Triangles

When my husband and I are sitting in different spots in a room, my dog has the amazing ability to form perfect triangles between us. It is as though she measures the distance prior to turning in a circle and curling up on the floor with a perfect view of each of us. We've turned it into a bit of a game, quietly moving from one area of the room to the other. After a few minutes she will shift in order to re-from the triangle. However, if we do it too many times she just lets out a big 'sigh' and stays in the same place as if to give up. Even if she seems to be fast asleep on the couch when we come in, she will get up within minutes, look at where we both are, and move to the spot that forms the corner of the triangle. It is just about the only time she is willing to lie on the floor.