What is the name of a 1980's (I am thinking) children's film where a boy I think on is birthday receives a gift enclosed in a large box. He opens it and a contraption was hidden within, somewhat like a car if memory serves me correct. He gets inside of it and it carries him off to a fantasy world where he is animated.
There are some parts of it I remember better than others. Initially I think he is taken to a forest where he falls in some kind of pit and has to escape these swamp like creatures. At another point he comes into contact with two kings/brothers who haven't spoken to each other for a number of years. One of them is affiliated with numbers and arithmetic while the other with letters and words. In the end he gets them to agree that they disagree and once again become friendly to each other.
In the end of the movie I think he is being chased and is upon a ledge.
That's is al I can remember
Thanks