annamarie1,
When a "family history" mission is started, north is straight up on the screen. The orientation of the screen may be rotated by clicking the arrows around the little pyramid to the left of the date (or using the Page Up or Page Down keys), and may be returned to the default (north up) orientation by clicking on the center of the little pyramid.
Let's say that you wanted to build one of the housing blocks diagrammed in this thread. Since roads on the screen run diagonally and roads on the diagram run vertically and horizontally, you'd have to (mentally) rotate the diagram to get it into a position where its roads line up with roads on the screen. Depending on how you rotated the diagram and how you rotated the screen, the block could be built with any of four orientations. For example, if your screen had the default (north up) orientation and you built a block so it looked like a diagram that had been rotated 45 degress clockwise, then that would be acting as if north was up-left in the unrotated diagram.
(Actually, the mirror image of the diagram could be considered essentially equivalent, so there are four more possible "orientations". And there's another complication--a pavilion cannot be built with its intersection in the eastsoutheast edge tile. Let's ignore both of those complications for now.)
Most of the time (in other words, ignoring teleportation and other strange things that walkers occasionally do to confuse us), when a building touches multiple connected road tiles, its random walker(s) will start his/her walk in a specific road tile and end his/her walk in a specific (maybe the same) road tile. The tile chosen is determined by the compass direction, as described in the thread linked in reply #64. If a building touches multiple connected road tiles, many (but not all) random walkers, including bazaar traders, will start their walk on the first non-roadblocked road tile adjacent to an edge that is encounted when going clockwise from the north corner of the building.
For example, let's look at the bazaar trader in Uthr Rhain's block that is linked in reply #63. If north in the diagram is up-right, then the first road tile adjacent to an edge that is encountered when going clockwise from the north tile of the bazaar is the roadblock. A bazaar trader won't start her walk in a roadblock, so she'll start in the the next tile encountered, which is part of the booth (and she'll stay inside the entertainment area since there's no way out). However, if north in the diagram is up-left (or any orientation other than up-right), then the first road tile adjacent to an edge that is encountered when going clockwise from the north tile of the bazaar will be on the loop road, so that's where the bazaar trader will start her walk.
I hope that's clear. It's not necessary to understand it all--for a long time, I avoided the problem by not giving random walkers the chance to start on the "wrong" street. For example, I wouldn't place any service provider next to a road that led out of a block (whether or not that road was roadblocked). Recently, though, I've taken advantage of knowing where "random" walkers start and finish their walks, so blocks in my recent cities may not work if they are rebuilt with a different orientation. (Now that I think about it, a few of the blocks in my older cities might not work either, since some of them have fairly long loop roads. )
[This message has been edited by Brugle (edited 01-21-2003 @ 03:16 PM).]