dented" src="pix/coscoscos.png" alt="nested cos equation">

<p>As z increases above 1.27, we get a square wave, then period doubling, and finally (ca. 1.97) chaos.
<!-- googling "cosine map" gets 1.974133 -->
</p>

<!--
(with-sound (:clipped #f :statistics #t) 
  (let ((angle 0.0) 
	(z 1.18)
	(incr (hz->radians 100.0)))
    (do ((i 0 (+ i 1)))
	((= i 20000))
      (let* ((result (* z (cos angle))))
	(do ((k 0 (+ k 1)))
	    ((= k 100))
	  (set! result (* z (cos result))))
	(set! angle (+ angle incr))
	(outa