Yup, that what hiems said something along the lines of "any mundane labyrinth"
Anyway, we'll combine that with the floor-marking numbering, which should enable us to "draw" a tree-like map. Something along the lines of:
I / I-I (take the first tunnel on the left / then first tunnel on the left)
/ I-II / I-II-I / I-II-I-I (first tunnel on the left / second tunnel on the left / first tunnel on the left)
/ I-II-I-II / I-II-I-II-I (and so on)
/ I-II-I-II-II
/ I-II-II
II / II-I
/ II-II / II-II-I
/ II-II-II
/ II-III / II-III-I
/ II-III-II
III / I