(possible (value ?v1) (group ?g) (id ?id2&~?id1))      (possible (value ?v2) (id ?id2))      (not (possible (value ?v1 | ?v2) (group ?g) (id ?id3&~?id2&~?id1)))   (possible (value ?v&~?v1&~?v2) (id ?id&?id1 | ?id2))   =>      (assert (impossible (id ?id) (value ?v) (priority ?p) (reason "Hidden Pairs"))));;; ######;;; X Wing;;; ######;;; **********;;; X-Wing-Row;;; **********(defrule X-Wing-Row      (priority ?p)   (technique (name X-Wing) (priority ?p))      (possible (value ?v) (row ?r1) (column ?c1))      (possible (value ?v) (row ?r1) (column ?c2&~?c1))      (not (possible (value ?v) (row ?r1) (column ~?c1&~?c2)))      (possible (value ?v) (row ?r2&~?r1) (column ?c1))      (possible (value ?v) (row ?r2) (column ?c2))      (not (possible (value ?v) (row ?r2) (column ~?c1&~?c2)))      (possible (value ?v) (row ~?r1&~?r2) (column ?c1 | ?c2) (id ?id))      =>      (assert (impossible (id ?id) (value ?v) (priority ?p) (reason "X Wing"))));;; *************;;; X-Wing-Column;;; *************(defrule X-Wing-Column      (priority ?p)   (technique (name X-Wing) (priority ?p))      (possible (value ?v) (row ?r1) (column ?c1))      (possible (value ?v) (row ?r2&~?r1) (column ?c1))      (not (possible (value ?v) (row ~?r1&~?r2) (column ?c1)))      (possible (value ?v) (row ?r1) (column ?c2&~?c1))      (possible (value ?v) (row ?r2) (column ?c2))      (not (possible (value ?v) (row ~?r1&~?r2) (column ?c2)))      (possible (value ?v) (row ?r1 | ?r2) (column ~?c1&~?c2) (id ?id))      =>      (assert (impossible (id ?id) (value ?v) (priority ?p) (reason "X Wing"))));;; #############;;; Naked Triples;;; #############;;; ****************;;; generate-triples;;; ****************(defrule generate-triples      (declare (salience 10))      (priority ?p)   (technique (name Naked-Triples) (priority ?p))   (size ?s)      (size-value (size ?sv1&:(<= ?sv1 ?s)) (value ?v1))    (size-value (size ?sv2&:(<= ?sv2 ?s)) (value ?v2&:(> ?v2 ?v1)))   (size-value (size ?sv3&:(<= ?sv3 ?s)) (value ?v3&:(> ?v3 ?v2)))   =>      (assert (triple ?v1 ?v2 ?v3)));;; *****************;;; naked-triples-row;;; *****************(defrule naked-triples-row   (priority ?p)   (technique (name Naked-Triples) (priority ?p))      (triple ?v1 ?v2 ?v3)      (possible (value ?v1) (row ?r) (id ?id1))      (not (possible (value ~?v1&~?v2&~?v3) (id ?id1)))      (possible (value ?v2) (row ?r) (id ?id2&~?id1))   (not (possible (value ~?v1&~?v2&~?v3) (id ?id2)))      (possible (value ?v3) (row ?r) (id ?id3&~?id2&~?id1))      (not (possible (value ~?v1&~?v2&~?v3) (id ?id3)))      (possible (value ?v& ?v1 | ?v2 | ?v3) (row ?r) (id ?id&~?id1&~?id2&~?id3))   =>      (assert (impossible (id ?id) (value ?v) (priority ?p) (reason "Naked Triples"))));;; ********************;;; naked-triples-column;;; ********************(defrule naked-triples-column   (priority ?p)   (technique (name Naked-Triples) (priority ?p))      (triple ?v1 ?v2 ?v3)      (possible (value ?v1) (column ?c) (id ?id1))      (not (possible (value ~?v1&~?v2&~?v3) (id ?id1)))      (possible (value ?v2) (column ?c) (id ?id2&~?id1))   (not (possible (value ~?v1&~?v2&~?v3) (id ?id2)))      (possible (value ?v3) (column ?c) (id ?id3&~?id2&~?id1))      (not (possible (value ~?v1&~?v2&~?v3) (id ?id3)))      (possible (value ?v& ?v1 | ?v2 | ?v3) (column ?c) (id ?id&~?id1&~?id2&~?id3))   =>      (assert (impossible (id ?id) (value ?v) (priority ?p) (reason "Naked Triples"))));;; *******************;;; naked-triples-group;;; *******************(defrule naked-triples-group   (priority ?p)   (technique (name Naked-Triples) (priority ?p))      (triple ?v1 ?v2 ?v3)      (possible (value ?v1) (group ?g) (id ?id1))      (not (possible (value ~?v1&~?v2&~?v3) (id ?id1)))      (possible (value ?v2) (group ?g) (id ?id2&~?id1))   (not (possible (value ~?v1&~?v2&~?v3) (id ?id2)))      (possible (value ?v3) (group ?g) (id ?id3&~?id2&~?id1))      (not (possible (value ~?v1&~?v2&~?v3) (id ?id3)))      (possible (value ?v& ?v1 | ?v2 | ?v3) (group ?g) (id ?id&~?id1&~?id2&~?id3))   =>      (assert (impossible (id ?id) (value ?v) (priority ?p) (reason "Naked Triples"))));;; ##############;;; Hidden Triples;;; ##############;;; ******************;;; hidden-triples-row;;; ******************(defrule hidden-triples-row   (priority ?p)   (technique (name Hidden-Triples) (priority ?p))      (triple ?v1 ?v2 ?v3)      (possible (value ?v1) (row ?r) (column ?c1))      (possible (value ?v2) (row ?r) (column ?c2&~?c1))      (possible (value ?v3) (row ?r) (column ?c3&~?c2&~?c1))      (not (possible (value ?v1 | ?v2 | ?v3) (row ?r) (column ~?c3&~?c2&~?c1)))      (possible (value ?v&~?v1&~?v2&~?v3) (row ?r) (column ?c1 | ?c2 | ?c3) (id ?id))   =>      (assert (impossible (id ?id) (value ?v) (priority ?p) (reason "Hidden Triples"))));;; *********************;;; hidden-triples-column;;; *********************(defrule hidden-triples-column   (priority ?p)   (technique (name Hidden-Triples) (priority ?p))      (triple ?v1 ?v2 ?v3)      (possible (value ?v1) (row ?r1) (column ?c))      (possible (value ?v2) (row ?r2&~?r1) (column ?c))      (possible (value ?v3) (row ?r3&~?r2&~?r1) (column ?c))      (not (possible (value ?v1 | ?v2 | ?v3) (row ~?r3&~?r2&~?r1) (column ?c)))      (possible (value ?v&~?v1&~?v2&~?v3) (row ?r1 | ?r2 | ?r3) (column ?c) (id ?id))   =>      (assert (impossible (id ?id) (value ?v) (priority ?p) (reason "Hidden Triples"))));;; ********************;;; hidden-triples-group;;; ********************(defrule hidden-triples-group   (priority ?p)   (technique (name Hidden-Triples) (priority ?p))      (triple ?v1 ?v2 ?v3)      (possible (value ?v1) (id ?id1) (group ?g))      (possible (value ?v2) (id ?id2&~?id1) (group ?g))      (possible (value ?v3) (id ?id3&~?id2&~?id1) (group ?g))      (not (possible (value ?v1 | ?v2 | ?v3) (id ~?id3&~?id2&~?id1) (group ?g)))      (possible (value ?v&~?v1&~?v2&~?v3) (id ?id& ?id1 | ?id2 | ?id3))   =>      (assert (impossible (id ?id) (value ?v) (priority ?p) (reason "Hidden Triples"))));;; #########;;; Swordfish;;; #########;;; *************;;; swordfish-row;;; *************(defrule swordfish-row   (priority ?p)   (technique (name Swordfish) (priority ?p))      (triple ?c1 ?c2 ?c3)      (possible (value ?v) (row ?r1) (column ?c1))      (not (possible (value ?v) (row ?r1) (column ~?c1&~?c2&~?c3)))      (possible (value ?v) (row ?r2&~?r1) (column ?c2))   (not (possible (value ?v) (row ?r2) (column ~?c1&~?c2&~?c3)))      (possible (value ?v) (row ?r3&~?r2&~?r1) (column ?c3))   (not (possible (value ?v) (row ?r3) (column ~?c1&~?c2&~?c3)))      (possible (value ?v) (row ~?r1&~?r2&~?r3) (column ?c1 | ?c2 | ?c3) (id ?id))   =>      (assert (impossible (id ?id) (value ?v) (priority ?p) (reason "Swordfish"))));;; ****************;;; swordfish-column;;; ****************(defrule swordfish-column   (priority ?p)   (technique (name Swordfish) (priority ?p))      (triple ?r1 ?r2 ?r3)      (possible (value ?v) (row ?r1) (column ?c1))      (not (possible (value ?v) (row ~?r1&~?r2&~?r3) (column ?c1)))      (possible (value ?v) (row ?r2) (column ?c2&~?c1))   (not (possible (value ?v) (row ~?r1&~?r2&~?r3) (column ?c2)))      (possible (value ?v) (row ?r3) (column ?c3&~?c2&~?c1))   (not (possible (value ?v) (row ~?r1&~?r2&~?r3) (column ?c3)))      (possible (value ?v) (row ?r1 | ?r2 | ?r3) (column ~?c1&~?c2&~?c3) (id ?id))   =>      (assert (impossible (id ?id) (value ?v) (priority ?p) (reason "Swordfish"))));;; #######;;; XY-Wing;;; #######;;; *******;;; XY-Wing;;; ******* (defrule XY-Wing   (priority ?p)   (technique (name XY-Wing) (priority ?p))      (possible (value ?x) (row ?r1) (column ?c1) (group ?g1) (id ?id1))      (possible (value ?y&~?x) (id ?id1))      (not (possible (value ~?y&~?x) (id ?id1)))      (possible (value ?x) (row ?r2) (column ?c2) (group ?g2) (id ?id2&~?id1))      (possible (value ?z&~?x) (id ?id2))      (not (possible (value ~?z&~?x) (id ?id2)))                  (test (or (= ?r1 ?r2) (= ?c1 ?c2) (= ?g1 ?g2)))   (possible (value ?y) (row ?r3) (column ?c3) (group ?g3) (id ?id3&~?id2&~?id1))      (possible (value ?z&~?y) (id ?id3))      (not (possible (value ~?z&~?y) (id ?id3)))                (test (or (= ?r1 ?r3) (= ?c1 ?c3) (= ?g1 ?g3)))                               (possible (value ?z) (row ?r4) (column ?c4) (group ?g4) (id ?id&~?id3&~?id2&~?id1))   (test (and (or (= ?r2 ?r4) (= ?c2 ?c4) (= ?g2 ?g4))              (or (= ?r3 ?r4) (= ?c3 ?c4) (= ?g3 ?g4))))   =>      (assert (impossible (id ?id) (value ?z) (priority ?p) (reason "XY-Wing"))));;; ######;;; Colors;;; ######;;; *********;;; color-row;;; *********(defrule color-row   (declare (salience -10))      (phase match)      (priority ?p)   (technique (name Duplicate-Color | Color-Conjugate-Pair | Multi-Color-Type-1  | Multi-Color-Type-2)               (priority ?p))   (possible (row ?r) (column ?c1) (group ?g1) (id ?id1) (value ?v))   (possible (row ?r) (column ?c2&~?c1) (group ?g2) (id ?id2) (value ?v))      (not (possible (row ?r) (column ?c3&~?c2&~?c1) (value ?v)))                        (color-pair ?color1 ?color2)      ;; Don't use a color previously used for this value.   (not (position-value-color (value ?v)                              (color ?color1 | color2)))      ;; Don't try to color the position if it's already colored.       (not (position-value-color (row ?r)                              (column ?c1 | ?c2)                              (value ?v)))   =>      (assert (position-value-color (row ?r)                                 (column ?c1)                                 (group ?g1)                                 (id ?id1)                                 (value ?v)                                 (color ?color1)))                     (assert (position-value-color (row ?r)                                 (column ?c2)                                 (group ?g2)                                 (id ?id2)                                 (value ?v)                                 (color ?color2))));;; ************;;; color-column;;; ************(defrule color-column   (declare (salience -10))      (phase match)      (priority ?p)   (technique (name Duplicate-Color | Color-Conjugate-Pair | Multi-Color-Type-1 | Multi-Color-Type-2)               (priority ?p))   (possible (row ?r1) (column ?c) (group ?g1) (id ?id1) (value ?v))   (possible (row ?r2&~?r1) (column ?c) (group ?g2) (id ?id2) (value ?v))      (not (possible (row ?r3&~?r2&~?r1) (column ?c) (value ?v)))                        (color-pair ?color1 ?color2)      ;; Don't use a color previously used for this value.   (not (position-value-color (value ?v)                              (color ?color1 | color2)))      ;; Don't try to color the position if it's already colored.       (not (position-value-color (row ?r1 | ?r2)                              (column ?c)                              (value ?v)))   =>      (assert (position-value-color (row ?r1)                                 (column ?c)                                 (group ?g1)                                 (id ?id1)                                 (value ?v)                                 (color ?color1)))                     (assert (position-value-color (row ?r2)                                 (column ?c)                                 (group ?g2)                                 (id ?id2)                                 (value ?v)                                 (color ?color2))));;; *******************;;; propagate-color-row;;; *******************(defrule propagate-color-row   (phase match)   (priority ?p)   (technique (name Duplicate-Color | Color-Conjugate-Pair | Multi-Color-Type-1 | Multi-Color-Type-2)               (priority ?p))   (position-value-color (row ?r) (column ?c1) (value ?v) (color ?color1))                                       (possible (row ?r) (column ?c2&~?c1) (group ?g) (id ?id) (value ?v))         (not (position-value-color (row ?r) (column ?c2) (value ?v)))                                 (not (possible (row ?r) (column ?c3&~?c2&~?c1) (value ?v)))                                  (color-pair ?color1 ?color2)      =>   (assert (position-value-color (row ?r)                                 (column ?c2)                                 (group ?g)                                 (id ?id)                                 (value ?v)                                 (color ?color2))));;; **********************;;; propagate-color-column;;; **********************(defrule propagate-color-column   (phase match)   (priority ?p)   (technique (name Duplicate-Color | Color-Conjugate-Pair | Multi-Color-Type-1 | Multi-Color-Type-2)               (priority ?p))   (position-value-color (row ?r1) (column ?c) (value ?v) (color ?color1))                                       (possible (row ?r2&~?r1) (column ?c) (group ?g) (id ?id) (value ?v))         (not (position-value-color (row ?r2) (column ?c) (value ?v)))                                 (not (possible (row ?r3&~?r2&~?r1) (column ?c) (value ?v)))