ups and downs (?.)
- Lissajous figure
- alternation
- back-and-forth
- chain of circumstances
- chain reaction
- chapter of accidents
- coming and going
- concatenation of events
- ebb and flow
- feast and famine
- flux and reflux
- ins and outs
- reciprocation
- rhythmic play
- seesaw
- seesawing
- sine wave
- teeter
- teeter-totter
- teeter-tottering
- teetering
- to-and-fro
- tottering
- vicious circle
- vicissitudes
- vicissitudes of fortune
- wigwag
