Tabu search
* smooth out the local optima

init X
while (fitness(X)<goodenough) {
    X' = mutate(X)               // exploitive
    if (not in tabu(X')) {       // tabu list exploritory
        pushTabu(X')                   // this is a fixed size stack!
        if (fitness(X')>fitness(X)) {
            X=X'
        }
    }
}

Tabu list: is a finite stack (finite depth - dropping oldest)

two types:
   genotype tabu
   mixing operator tabu