(defn pm-chunk [data chsize]
  (apply str
         (interleave (map #(apply str (interpose " " %))
                          (partition chsize chsize nil data))
                     (repeat \newline))))


##</code><code>##

user=> (print (pm-chunk  ["a" "bb" "c" "d" "e" "f" "g" "h"] 3))
a bb c
d e f
g h