Lissajous figure
back-and-forth
battledore and shuttlecock
beat
chain
coaction
coming and going
commutation
complementary distribution
concurrence
consecution
cooperation
counterchange
cross fire
cyclicalness
ebb and flow
engagement
exchange
fluctuation
flux and reflux
give-and-take
interaction
interchange
interchangeableness
intercommunication
intercourse
interlacing
intermeshing
intermittence
intermittency
intermutation
interplay
intertwining
interweaving
interworking
lex talionis
measure for measure
mesh
meshing
meter
mutual admiration
mutual support
mutual transfer
mutuality
order
oscillation
pendulation
pendulum motion
periodicalness
sequence
succession
abruptness
attrition
cadence
collocation
crescendo
ebb
gradation
intermingling
intermixture
iteration
patter
permutation
progression
pulsations
readjustment
recital
recurrence
refrain
reiteration
reminder
vicissitude
whirl