Tarskies World is a Turbo Prolog implementation of on of
these AI block worlds. There was a lot of rumor about this
type of systems in the '70, whith AI researchers believing
that this type of systems could be extended to real world
situation. However, this attempt failed completely.
Today, Tarskies World is a nice toy and an exercise in logic
programming (Prolog). You can download the source
(get password) for Turbo