Alternation

the alternation of day and night

alternation of summer and winter

alternation between night shifts and day shifts

alternation of feelings between hope and fear

There are Anthems to be found amongst them , where every syllable has its just length ; each part of a sentence its proper pause : where the words are not confused by perplexing alternations, or rendered tedious by unnecessary repetitions

dative alternation; locative alternation

1932, Harold Scott Macdonald Coxeter, The densities of the regular polytopes, part 2, reprinted in 1995, F. Arthur Sherk, Peter Mcmullen, Anthony C. Thompson, Asia Ivić Weiss (editors), Kaleidoscopes: Selected Writings of H. S. M. Coxeter, page 54, This case suggests that the alternation of a polyhedron should be bounded by actual vertex figures and alternated faces. The case of the cube is in agreement with this notion, since the alternated square is nothing.