RFC-3092 compatible metasyntactic variable name generator.

foo.el

(eval-when-compile
  (require 'cl-lib))

(defun foo (count)
  "Inserts at point position COUNT metasyntactic variable names separated by spaces.
Compatible with RFC-3092."
  (interactive "p")
  (insert
   (mapconcat
    'identity
    (cl-loop
       repeat count
       with foos = '("bar" "baz" "qux" "quux" "corge"
                     "grault" "garply" "waldo" "fred"
                     "plugh" "xyzzy" "thud")
       for foo = (nth (random (length foos)) foos)
       collect foo)
    " ")))