Russell
"This characteristic attribute of nature to repeat herself, and to do so in waves or striations of periodicities, is because of the dual character of force to express itself always in equal opposition of force." [Cycle of Motion]
See Also
androgynous
Androgyny
Balance
doubly charged mass
doubly charged masses
Dual
Duality
Equilibrium
Father-Mother
mate-pairs
Polar
Reciprocal
Seesaw