Strips_op move_floorToStack = new Strips_op("move ?b1 off ?f onto ?b2",
                                                "?b1 on ?b2|?b1 at ?t",
                                                "?b1 on ?f|?b1 at ?t|?b2 at ?t",
                                                "?b1 on ?f|?b1 at ?t|?b2 at ?t");

    Strips_op move_stackToStack = new Strips_op("move ?b1 off ?b2 onto ?b3",
                                                "?b1 on ?b3|b1 at ?t|b2 at ?t",
                                                "?b1 on ?b2|b1 at ?t|b3 at ?t",
                                                "?b1 on ?b2|b1 at ?t|b3 at ?t");

    Strips_op move_stackToFloor = new Strips_op("move ?b1 off ?b2 onto ?f",
                                                "?b1 on ?f|?b1 at ?t|b2 at ?t",
                                                "?b1 on ?b2|b1 at ?t",
                                                "?b1 on ?b2|b1 at ?t");