<> (explode ?*) (str (?*))
<> (reverse (str (?h ?t))) (reverse/l ?t (?h))
<> (reverse (str (?h))) (?h)
<> (reverse/l (?h ?t) ?l) (reverse/l ?t (?h ?l))
<> (reverse/l (?h) ?l) (str (?h ?l))
<> (implode str ?*) (?*)
(implode reverse (explode hello))