Blanchard and Fabre (1994) have considered description of symbolic systems by sequences obtained by iteration of two mappings $1, and d" defined by g,(u) = u [u], and L/, J u[u]:, m here the word [u], is obtained from a word u by removing the last ,j symbols. They stated a conjecture thal the iteration of (I, results in an automatic sequence. We prove here that t/, ix. while (1) 1s not, a 2.automatic sequence. Our result is obtained by investigation of two wider classes of sequences. *