
The spiral stairs inside Hometree

Koranu making a spiral design
Spiral (Na'vi name: 'Iheyu) is a spiritual concept in Na'vi culture, not yet fully understood.[citation needed]
Associated with the interweaving of tree roots and Eywa, the spiral is the embodiment of life and the interconnectedness of all things on Pandora: among the songs of the Na'vi is the Song of the Spiral, which embodies unity between the people, the forest, and Eywa. The spiral can also refer to the support structure located in each Hometree. In the center of each Hometree grows a spiral formation that serves to support the general structure of the giant tree and is used by the Na'vi as a natural staircase.
At the base of the Hometree, the spiral is wide and thanks to the mushrooms that grow on it, it resembles a real ladder with steps, but closer to the top it turns into uncoiling branches, reminiscent of the bases of DNA, so you have to jump further to get to the nest of tamed banshees.