5
+ /
ov
+
+ |
/| + +
/ | |/o
/ o + |
/ +o+--+--+
+ + \
o |\ + +
+--+--+ \ |o \
/ \| + 4
+--+o-+ +-o+
o
/
+
4 = Mega-Maze Basement (Part 4)
5 = Mega-Maze Basement (Part 5)
Here is the universal key.