alternate
back and fill
bob
bobble
careen
change
chop and change
coggle
dangle
dither
ebb and flow
equivocate
flounder
flutter
go through phases
hesitate
intermit
lack regularity
librate
lurch
nutate
oscillate
pendulate
pitch
recur
reel
resonate
return
reverse
ring the changes
rock
roll
scruple
seesaw
shake
shift
shilly-shally
shuffle
stagger
swag
sway
swing
teeter
teeter-totter
tergiversate
toss
totter
turn
vacillate
change state
displace
move
fluctuated
fluctuates
fluctuating