Another special mitzvah of Sukkot is the shaking together of the "Four Species" -- the etrog (citron), lulav (palm branch), three hadassim (myrtle branches), and two arovot (willow branches).
Each day of Sukkot (except the Sabbath), we shake the "four kinds" during the daytime.
Hold the lulav, hadassim, and arovot in the right hand, with the lulav's "spine' "facing you.
Say the appropriate blessing(s), then take the etrog in the left hand with the point, or "pitom," up, bring it together with the other three kinds, and shake it.
One explanation, among many, is that each of the four kinds represents a different type of Jew.
The fact that the mitzvah requires all four kinds symbolizes our oneness as a people: we all need one another. And the four species are waved in all four directions, and up and down, signifying that G-d is everywhere.