Hi max1000000,
I like that type of winding layout.
They often do that on small supply transformers, presumably so that
you can see there is good insulation between the windings.
Insulation on the concentrically wound type can be just as good of
course, but you can't see it.
Also you can see that the window space is evenly shared between
windings, thats not so easy to judge on the other type.
As to your question, how to wire it for 115 volt working ....
If your power needs are less than about five or six watts, then
just use any pair on the primary side for the supply connections.
And ignore the remaining pair.
That will be fine as either primary winding will work independantly.
However, as Rolf says, you need them both for maximum output current.
Which takes us to the question of phasing.
This could be determined by connecting one side of the remaining pair
to your neutral, and measuring the difference between the remaining
terminal and your incoming supply live connection point.
If it were out of phase with the existing supply, you would measure
230 AC volts between them.
If it were in phase, there should be no difference, or maybe a very
slight reading.
There are other ways of course, using other equipment, but with
minimum equipment, that is the approach i would take.
In all likelihood you would be fine using only one winding anyway.
I hope the above is easy to understand, i re-wrote it a couple of
times, to try and make it clear.
If its not clear, maybe someone could write it in a clearer way.
Sometimes what is clear to me, is not clear to others.
Best of luck with it,
John