A second wave of bubblegum ran until 1977.
In some of those situations, one may describe such a family of waves by a function                     F        (        A        ,        B        ,                ;        x        ,        t        )              {\displaystyle F(A,B,\ldots ;x,t)}   that depends on certain parameters                     A        ,        B        ,                      {\displaystyle A,B,\ldots }  , besides                     x              {\displaystyle x}   and                     t              {\displaystyle t}  
 In a mechanical wave, stress and strain fields oscillate about a mechanical equilibrium

