Hello,
yes, that is just the way I work at the moment.
I lead the Marble on the right path and receive the A and B by this.
Due to some errors I couldn't resolve, my Marble-position went wrong.
At this moment I try desparate to retrieve my Marble-position based on A and B.
It is not always easy being me...
But you are right - in theory.
Chrisir
