Based on tries, new words formed by adding one letter at the beginning or end:
a - eirst b - airest c - satire d - striae e - terais f - bestir g - bister h - bistre k - biters l - tribes m - citers n - steric o - trices p - direst r - driest s - stride t - resite u - reties v - refits w - resift z - rifest
