What is the symbolism of Labyrinth in Grisaia no Meikyuu?


The first VN/season deals with the fruit of Grisaia, the sins (or sorrow) of
the girls.

[Is the Fruit of Grisaia an actual
fruit?](https://anime.stackexchange.com/questions/3139/is-the-fruit-of-
grisaia-an-actual-fruit)

Now, what is _Labyrinth_ in the title of the second game supposed to mean?

