Einstein's Theory Of Relativity.
For every action, there is an equal and opposite reaction.
Black and White.
Matter & Antimatter
Kirk & Klingons
Batman & Penguin
Courageous Cat & Master Cylinder
Tweety & Sylvester
Toto & Flying Monkeys
Frodo & The Ring
Yoda & Darth

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O'TEDDY BIN-SWIMIN