(defun square (x) (* x x))

(defun add-three (x y z) (+ x y z))

(defun palindrome (input-list)
  (append input-list (reverse input-list)))

(defun palindrome-elided (input-list)
  (append input-list (cdr (reverse input-list))))

(defun repeat-ones (iterations)
  (cond ((<= iterations 0) nil)
	(t (cons 1 (repeat-ones (- iterations 1)))))) 

(defun get-first-hexachord (input-series iterator)
  (cond ((>= iterator 6) nil)
	(t (cons (car input-series)
		 (get-first-hexachord (cdr input-series) (+ iterator 1))))))

(defun cheap-second-hexachord (input-series)
  (reverse (get-first-hexachord (reverse input-series) 0)))

(defun get-second-hexachord (input-series iterator)
  (cond ((>= iterator 6) input-series)
	(t (get-second-hexachord (cdr input-series) (+ iterator 1)))))

(defun transpose-row (input-series transposition-value)
  (cond ((null input-series) nil)
	(t (cons (mod (+ (car input-series) transposition-value) 12)
		 (transpose-row (cdr input-series) transposition-value)))))

(defun add-register (input-series base-value)
  (cond ((null input-series) nil)
	(t (cons (+ (car input-series) base-value)
		 (add-register (cdr input-series) base-value)))))

(defun rotate-left (input-hexachord)
  (append (cdr input-hexachord) (list (car input-hexachord))))

(defun rotate-right (input-series)
  (reverse (rotate-left (reverse input-series))))

(defun kreuzspiel (input-series)
  (append (rotate-left (get-first-hexachord input-series 0))
	  (rotate-right (get-second-hexachord input-series 0))))

(defun series (values start-time)
  (if (null values)
      nil
      (let* ((current-value (car values))
	     (current-rhythm (float (* 1/12 (+ current-value 1)))))
	(cons (new midi
		:time start-time
		:keynum (+ 60 current-value)
		:amplitude current-rhythm
		:duration current-rhythm)
	      (series (cdr values) (+ start-time current-rhythm))))))