(defun idea (tbl &optional (enough 2))
  (with-slots (rows left right) tbl 
    (when (> (length rows) enough)
      (let* ((any  (anyv rows))
	     (west (furthest tbl any rows)))
	(multiple-value-bind (east c)
	    (furthest tbl west rows)
	  (let* ((all   (rows-sorted-along-x tbl rows west east c))
		 (half  (floor (/ (length all) 2)))
		 (above (copy-table tbl))
		 (below (copy-table tbl)))
	    (setf (table-rows below)  (vector! (subseq all 0 half))
	          (table-rows above)  (vector! (subseq all half))
	          left  below
	          right above)
	    (idea left  enough)
	    (idea right enough))))
      tbl)))

(defun rows-sorted-along-x (tbl rows west east c &aux all)
  (dov (one rows)
    (let ((place  (x (dist tbl one west)
		     (dist tbl one east)
		     c)))
      (push (cons place one) all)))
  (mapcar #'cdr (sort all #'< :key #'car)))
	
(defun x (a b c)
  "Find x of (x,y) that is distance 'a' from (0,0) and 'b' fron (c,0)"
  (if (zerop c)
      0
      (/ (+ (* a a) (* c c) (* -1 b b)) 
	 (* 2 c))))

(defun y (a x)
  "Find x of (x,y) that is distance 'a' from (0,0) and 'b' fron (c,0)"
  (sqrt (+ (* a a) (* -1 x x))))

(defun printt (tbl &optional (depth 0) (prefix "") (str t) (padding "|  ") )
  (when tbl
    (dotimes (i depth) (format str "~a" padding))
    (format str "~a~a~%" prefix (length (table-rows tbl)))
    (printt (table-left tbl) (1+ depth) "<" str padding)
    (printt (table-right tbl) (1+ depth) ">" str padding)
    t)
)

(deftest !idea1 ()
  (dolist (what '(15 10 5 2))
    (!idea1-prim  "data/autos32.lisp" what)))

(defun !idea1-prim (f &optional (enough 30))
  (print `(,enough
	   ,(time-it 1 (idea (slurp f) enough)))))