Print star

star.lisp

(defun star (input)
  "Make star."
  (let* ((l (length input))
         (lo (- l 1))
         (ll (- (* 2 l) 1))
         (star (make-array (list ll ll) :initial-element #\Space)))
    (dotimes (i l)
      (let ((a (+ 0 i))
            (b (- ll i 1)))
        (map nil (lambda (x y) (setf (aref star x y) (aref input i)))
             (list i b lo lo a a b b) (list lo lo i b a b a b))))
    (dotimes (i ll)
      (dotimes (j ll)
        (write-char (aref star i j)))
      (write-char #\Newline))))