I'm not sure if OBOD incorporated these to their teachings but I find the Druidic cosmology fascinating to study and learn. Actually if you enjoy the latest and last installment of Harry Potter series, the Deathly Hallows, you could possibly add some pop culture magic to your presentation and that would catch and draw your audience's attention and interest. It's my love of symbolism and synchronicity that piqued my interest to watch the movie : the symbol of the deathly hallows.
Incidentally I was learning about the cosmology of the Druidic tradition and one of the concepts I ran into was there Three Sacred Hallows of Fire, Tree, and Well (ADF cosmology). These are symbols that correspond to the three worlds of the Celtic cosmology. The Well is connected to the Underworld. The Tree is connected to the Middleworld, our world. The Fire is connected to the Upperworld, that of the heavens and Higher realms.
The hallows correspond as well as the three groups of spirits that Ancient Celts worship (Gods, nature spirits, and ancestors). Basically the Hallows embody the spiritual beliefs around which their magick revolve.
Each of these "Druidry Hallows" I think fits smoothly into one of the components of the "Deathly Hallows" symbol:
- In the movie, the triangle represents the Invisibility Cloak. In alchemy of West and in tattvic symbolism of the East, Fire is always represented as an upright triangle. The Fire as I said is connected to the Upperworld which is the realm of the Gods and Goddesses who are often "invisible" to us. In other orders, this is called the world of "Sky".
- The circle represents the Resurrection Stone. The Well can be perfectly represented as a circle or ring because of it's obvious shape. It is associated with the Underworld, which is always seen in every culture as the place of "death and rebirth." Some Druids called it the world of "Sea" or "Water" where the spirits ancestors reside.
- The vertical line represents the Elder Wand. The Tree is just right to be the vertical line in the center in my opinion, just like a bridge linking and uniting the opposite worlds of Fire and Well. The Tree according to the Druids, is associated with the Middleworld where power of "life and growth" manifests. It is also known as The world of "Land" -- the sacred realm of plants, stones, animals, humans and their Spirits.