alternated
al-ter-nat-ed
verb
Switched repeatedly between two or more different states or actions.
"She alternated between joy and despair."
verb
Occurred or caused to occur in a regular, repeating sequence.
"The colours alternated red and blue."
Thesaurus
Synonyms: alternate, alternative, substitute, secondary, take turns, understudy, jump, surrogate, replacement, flip, interchange, flip-flop