anchor.diff:        (rec (num->bv (bv->num iv) n)))))
   
   (defun bvlist-gen (n &optional (init #*10))
  -  "return a function representing prbs-N. The returned function takes a single argument which is the number of the next n-bit bit vectors to generate from the sequence (default 1 value)."
  +  "=> lambda (x)
  +
  +Create a prbs-`N` function. The function takes a single argument which is the number of the next `N`-bit bit vectors to generate from the sequence (default 1 value).
  +
  +`IV` can be provided as an initial bit-vector."
     (let ((v (make-prbs n init)))
       (lambda (&optional (c 1))
  -      (loop for i from 1 to c collecting
  +      (loop repeat c collecting
              (let ((b (dcar v)))
                (setq v (dcdr v))
                b)))))
         
  -(defun bit-gen (n &optional (init #*10))
  +(defun bit-gen (n &optional (skip 0) (init #*10))
     "return a function representing prbs-N. The returned function takes a single argument which is the number of the next bits to generate from the sequence (default 1 bit)."
     (let ((gen (bvlist-gen n init))
           (res #*))
  
positive.code:     (concatenate 'bit-vector
                   (subseq bv 1)
                   (bitbv (newbit bv)))))
  
  (defun make-prbs (n &optional (iv #*10))
    "=>  lazy list of repeating `N`-bit bitvectors
  
  
negative.code: 
  (in-package :prbs)
  
  (declaim (optimize (debug 0) (safety 0) (speed 3)))
  
  (defun prbs-n (bv taps)
    "=> bit-vector
  
  