Not sure if I use this the right way, but:
If I make a vertical path (non-liniar) A
and make a horizontal path (non-liniar) B
I make A transparent, B opaque.
I make them cross each other.
Part of A that is close to B, will now be visible.
Btw. are there easier ways of switch something like a path or text on and off, beside using the transparency in setColor()?