More homework and clues for all of you somanauts out there. Previously we have been exploring variations on concentric circles (feminine) in several posts and now we add the masculine line in the form of the pyramid and some of the platonic solids. Somanautics requires a clear flow of perception, a good imagination, and lots of patience and curiosity. Go for it!
We’ll start with the square based pyramid 
as seen here. From the apex or top four lines descend, one to each of the four corners of a square, creating four triangles. This one shown is solid, but we can just as well imagine a pyramid of energy or as a light field. 
As we see with B.K.S. Iyengar, the basic sitting posture creates a pyramidal shape. If we could channel our inner Brahma, we could imagine four heads each looking out to the four directions, N,S, E and W, with head and tail orienting to heaven and earth to complete the six sacred directions. 
There are many ways to explore this energy field. Here is one. Notice Brahma’s enlarged crown chakra. As you sit in whatever meditation position speaks to you, find the crown chakra space above your head and open it, wake it up. Let this be the apex. Imagine the inhalation traveling down from the apex spreading down the pyramid, ever widening in all four directions as it descends. This is a feminine inhalation, descending and widening. Feel grounded, rooted, stable. Imagine the masculine exhalation traveling up from the root chakra straight up the center channel to the crown chakra. Feel tall, open and spacious. As the inhalation moves down, keep the inner channel tall. As the exhalation flows, keep the width at all levels of the pyramid. Masculine and feminine energies move in perfect harmony. Let your cells and connective tissue structures feel the shape, expanding as they are supported by the field. This is ‘sthira sukham asanam’.
Another possibility begins with a mini pyramid centered on the root chakra. 
Let it breathe. Then slowly allow it to increase in size, keeping the center point of the base stable. Draw the apex up through the chakras observing where the body opens and where there is resistance. Be gentle and clear. Feel the pyramid expanding on the in breath, widening and releasing all unnecessary tension on the exhalation. Grow the pyramid until it reaches up past your crown chakra. Which of the four directions opens more easily? Which is the most resistant?
The square base pyramid is actually half of an octahedron, one of the five platonic solids.
A triangular based pyramid is known as a tetrahedron, another platonic solid. 
Notice that the tetrahedron is asyymetrical. If we use it as a form for sitting we have to choose whether to have the base pointing forward or backward. Each offers a different inner experience. Try both. See if one or the other is more appealing.
If we take two tetrahedrons, put them together, one apex pointing up, the other down, we find a stellated octahedron. Here are two stellated octahedrons for your imagination to run with. Lots of fun can be had with the energy fields these create and we will come back to them in an upcoming post. They are a bit more complex so it may take a while. Enjoy!