;; Sun Oct 17 00:32:48 CEST 2004

(defparameter *colinear-segments*
  '((p0 p1)
    (p0 p2 p4 p6)
    (p0 p3 p7 p9)
    (p0 p5 p8 p10)
    (p1 p2 p3 p5)
    (p1 p4 p7 p8)
    (p1 p6 p9 p10)));;*colinear-segments*


(defun binomes (set)
  (do ((first set (cdr first))
       (results '()))
      ((null first) results)
    (do ((second (cdr first) (cdr second)))
        ((null second))
      (push (list (car first) (car second)) results))));;binomes


(let ((count 0))
  (do  ((css  *colinear-segments* (cdr css)))
       ((null (cddr css)) count)
    (dolist (base (binomes (car css)))
      (do ((left (cdr css) (cdr left)))
          ((null (cdr left)))
        (when (member (first base) (car left))
          (dolist (right (cdr left))
            (when (member (second base) right)
              #-() (dolist (opo (set-difference
                                 (delete-duplicates
                                  (intersection (car left) right)) base))
                     (print (list (first base) (second base) opo)))
              (incf count (length (set-difference
                                   (delete-duplicates
                                    (intersection (car left) right)) 
                                   base))))))))))