;;Non-Blocks World Examples (e.g., 'the president has a cat').

(subclass President Position)

(subclass Cat Animal)

(subclass Dog Animal)

(instance George Human)

(instance Bill Human)

(instance Fido Dog)

(instance HammerTheTool Artifact)

;;Blocks World Extensions

;;Our blocks world has only blocks, cones, pyramids, and the table.

(subclass Block Artifact)

(subclass Cone Artifact)

(subclass Pyramid Artifact)

(subclass Table Artifact)

;;We use orange as a color, so first define complementary colors...

(subclass ComplementaryColor ColorProperty)
(disjointDecomposition ComplementaryColor Orange Green Purple)
(documentation ComplementaryColor "A color formed by mixing two
primary colors.")

(instance Orange ComplementaryColor)
(documentation Orange "The &%Attribute of being orange in color.")

(instance Green ComplementaryColor)
(documentation Orange "The &%Attribute of being green in color.")

(instance Purple ComplementaryColor)
(documentation Orange "The &%Attribute of being purple in color.")

;;We also allow blocks world objects to be made of iron, concrete, or wood
;;to provide some more modifiers other than just colors...

(subclass Iron Substance)

(subclass Concrete Substance)

(subclass Wood Substance)

(instance BlocksWorldIron Iron)

(instance BlocksWorldWood Wood)

(instance BlocksWorldConcrete Concrete)

;;In particular, the following unique objects exist...

(instance RedBlock1 Block)

(instance TheTable1 Table)

(on RedBlock1 TheTable1)

(instance LargePyramid1 Pyramid)

(material BlocksWorldIron LargePyramid1)

(instance BlueCone1 Cone)

(material BlocksWorldConcrete BlueCone1)

(instance OrangeBlock1 Block)

(attribute RedBlock1 Red)

(attribute OrangeBlock1 Orange)

(attribute BlueCone1 Blue)

(instance TowerBlockBase Block)

(instance TowerBlockMiddle Block)

(instance TowerBlockTop Block)

(instance Tower1 Tower)

(member TowerBlockBase Tower1)

(member TowerBlockMiddle Tower1)

(member TowerBlockUpper Tower1)

(on TowerBlockBase TheTable1)

(instance TowerBlockUpper Clear)

;;Define "clear" to mean that nothing is on top of an object.

(=> (instance ?OBJECT Clear)
    (not (exists (?OTHER)
		 (on ?OTHER ?OBJECT))))

;;Define a tower as a collection of at least three objects,
;;each on top of another object in the tower, or the table.

(subclass Tower Collection)

;;All objects in the tower are Blocks world objects: Blocks, Pyramids, or Cones
(=> (instance ?TOWER Tower)
    (=> (member ?OBJ ?TOWER)
        (or (instance ?OBJ Block)
            (instance ?OBJ Pyramid)
            (instance ?OBJ Cone))))

;;Each object in a tower is on top of either the table or another object in the tower
(=> (instance ?TOWER Tower)
    (forall (?OBJ)
       (=> (member ?OBJ ?TOWER)
	   (exists (?OTHER)
		   (and (on ?OBJ ?OTHER)
			(or (instance ?OTHER Table)
			    (member ?OTHER ?TOWER)))))))

;;There are at least three objects in the tower

(=> (instance ?TOWER Tower)
    (exists (?OBJ1 ?OBJ2 ?OBJ3)
	    (and (member ?OBJ1 ?TOWER)
		 (member ?OBJ2 ?TOWER)
		 (member ?OBJ3 ?TOWER)
		 (not (equal ?OBJ1 ?OBJ2))
		 (not (equal ?OBJ2 ?OBJ3))
		 (not (equal ?OBJ1 ?OBJ3)))))

;;Note that we should be able to deduce that TowerBlockMiddle is on TowerBlockBase
;;and TowerBlockUpper is on TowerBlockMiddle since the base is on the table and the
;;top block is clear.