You can display code and/or the results of code execution for many languages.

Define an add code block:

(+ 1 2 3 4)

Insert the result of calling the add code block:

10

Define a reverse function:

(defun reverse (list)
  (let (value)
    (dolist (elt list value)
      (setq value (cons elt value)))))

Insert a block that uses reverse and displays the results:

(reverse (list 1 2 3 4))

Call the menu code block in header.org to insert another copy of the menu: