As I mentioned, not everyone uses a circle. There are some groups who feel very connected to a spiritual trinity and prefer to gather in the shape of a triangle. I’ve even participated in a ritual where the group had enough members to gather in the shape of a pentagram. I know of an Egyptian group who tries to recreate the Great Pyramid and gather in a perfect square, with the Priestess standing on a small platform in the center to represent the center point of the pyramid.
The format you use to gather depends on what you feel drawn to. What you want to align your energies with and how you think you can best do that.
Free eBooks (Can Be Downloaded):
Emilie Kip Baker - Stories From Northern MythsWilliam Wynn Westcott - Historic Lecture Golden Dawn
Anthony Arndt - Asatru The Northern Way