In Western Esoteric imagery, a common motif is that of two pillars on the sides of a Gateway, which the astral traveler or visionary must pass through. One pillar is black, the other white. This symbol has been in literature for thousands of years, including a mention in the Bible where they are at the doorway of the Jewish Temple of Solomon. I am currently working on a book cover on the subject of mystical visualization as seen in Kabbalah, that is Jewish mysticism, and I've put these two famous pillars in my cover design. The blue globes on top of the pillars come from Masonic imagery, which in turn borrowed some material from the older mysticism. The blue globes are not finished; I will be rendering them as planet and sky. The whole cover should be done in a few days.
Photoshop on Cintiq, February 2017.