The Clone Wars - S3E15 - "Overlords"

Throughout the scene in "Overlords" where Anakin uses the Force to compel the Daughter and the Son to release Obi-Wan and Ahsoka, he uses his left, biological arm to control the Daughter (who represents the light side) and his right, mechanical arm to control the Son (who represents the dark side).

This arrangement has some significance.  At the very least, it foreshadows the association between artificial limbs and the dark side of the Force that Anakin will exhibit as Darth Vader.  In a comment to Luke in Return of the Jedi, Obi-Wan mentions this connection:  "He's more machine now than man, twisted and evil."

(The different qualities of Anakin's arms also hold significance in a scene in "Crisis at the Heart" [S6E7], which I've written about here.)