Working out rotation

Hey all.

I've worked my way through the GPGT book and started working on something of my own. All going well till I tried to place a wall around my village.

I needed to rotate some of the wall segments to line up with existing buildings in the village. However, the coverage of GPGT is very slim (page 152).

How does it work?

In inspector I worked out that the fourth element determines Z-rotation, but what controls X & Y rotation? Changing the values in element two and three make no changes to the wall segment?

Thanks
Dale