There are plenty of pictures in my various article that show the Artificial Loop in action, and you can download any of the various saves if you want to take a closer look.
I completely agree with Nero's analysis of WHY the technique works, but my convention is rotated by 90 degrees to the right, so that the screen positions match those on a wall clock. Noon, in other word, is the top right corner of the housing block.
In Zeus and Poseidon, City North is in the upper left corner of the screen, and to match the glyphies to the screen you rotate them 45 degrees to the left.
Looking at the convention from a screen perspective, what you'll actually see is:
-----12-----
--11**01--
-10****02-
09******03
-08****04-
--07**05--
-----06-----
The important consideration is that TWO locally unconnected segments of roadway touch the Fountain and the Infirmary. Normally, corners (12,3,6,9) are ignored and the program examines the available road connections starting at position 1. The entry and exit points are usually identical.
In this special case, which is unique to the Infirmary and Fountain, the return path is evaluated starting at 0, which is the 12 o'clock position, so TWO locally disconnected segments of roadway are considered.
The Outbound segment can touch any tiles NOT CONNECTED to 12 o'clock.
The Return segment can touch any tiles CONNECTED to 12 o'clock.
An awareness of how entry and exit points are determined is quite important when you're laying out a city, and I often use a back alley supply road to service the interior of a city block when my Agoras are located on the East (upper right) or South (lower right) side of a Housing Block. There are plenty of working examples on my site.
[This message has been edited by MarvL (edited 09-30-2001 @ 01:02 PM).]