In the third lecture of the Astrology course, the zodiac sign Gemini (May 21 - June 21) is explained. Quoted from the lecture:

"The astrological sign of Gemini illustrates a function of duality. When you observe the astrological sign of Gemini, you will see two columns or two rods placed side by side. Of course, this illustrates two brothers, twins who work together, and this illustrates a fundamental axis of nature."

Read the lecture transcription.