Ferris wheel
Lissajous figure
alternate
alternately
alternation
back and fill
back and forth
back-and-forth
backward and forward
backwards and forwards
battledore and shuttlecock
cant
carousel
chute-the-chutes
chutes
coaction
come and go
coming and going
complementary distribution
concurrence
cooperation
crossruff
ebb and flow
engagement
flounder
fluctuate
flux and reflux
flying horses
go through phases
hitch and hike
in and out
incline
interaction
interchange
intercommunication
intercourse
interlacing
intermeshing
interplay
intertwining
interweaving
interworking
lean
list
lurch
merry-go-round
mesh
meshing
metronome
mutatis mutandis
move
play
plaything
toy
seesawed
seesawing
seesaws
arahantship
atmospherical
best-case
book-reading
brainwriting
climatological
corkboard
enterprise-specific
escapar
flutelike
hydrographical
invacuum
invulnerability
jammies
jingle-jangle
justcrowd
letdown
long-past
lustiest
no-win
omnipresence
on-base
one-note
out-of-control
peristaltic
plosive
pyramide
schoolwork
sejauh
short-period
singsong
sinlessness
snigger
spheral
technologiesv
tuneable
ubiquity
ultradian
well-bound
Esau