A problem - how in prolog

[Paul Nothman]

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This problem was recently in a Mathematics competition. Although I
completed
it through logic and mathematics, without the aid of a computer, I'm
wondering if & how it could be answered using prolog. (Preferably
Strawberry
Prolog or AMZI)

The problem is as follows:
------
World theme park has seven attractions which are so far apart that there
needs to be a network of monorails, called zoomtracks, to transport the
patrons between attractions. There is exactly one zoomtrack between each
pair of attractions. Each zoomtrack can only transport patrons in one
direction.
The netwrork is contstructed so that wo friends can always meet at a third
attraction after exactly one trip each from any two attractions.
Hint: Each attraction leads to and is led to by 3 other attractions. There
are 21 zoomtracks altogether.

What is the entire configuaration of the theme park if the followning
details exist: (the first letter of each line is the attraction from which
the zoomtrack comes and the one beside it is where the zoomtrack leads to).

SU
SO
ST
UO
UN
UP
OT
ON
NP
TU

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- Joel Nothman jnot...@hotmail.com (see above note)