Just a little amendment to the shape of the extrusion head could make some interesting shapes. This small change might result in a stronger structure than a simple ring shape could create.
Perhaps something like a cactus tower in cross-section.
The cross section shown is a bit dried out, from a saguaro cactus (Carnegiea gigantea).
The cut off pieces in a ring around the center of the plant stem are actually long very strong poles that run all the way up through the cactus stem called saguaro ribs.