An "add-a-gram" is a sequence of words formed by starting with a 3-letter word, adding a letter and rearranging to form a 4-letter word, and so on. For example, here are add-a-grams of the words "CREDENTIALS" and "ANACHRONISM":
ail + s =
sail + n =
nails + e =
aliens + t =
salient + r =
entrails + c =
clarinets + e =
interlaces + d =
CREDENTIALS (length 11)
mar + c =
cram + h =
march + s =
charms + o =
chromas + n =
monarchs + i =
harmonics + a =
maraschino + n =
ANACHRONISM (length 11)
Переход от interlaces к credentials впечатляет. Надо попробовать на русском на досуге.