Regular cube (2 points)
Ahoy, officer
knowledge of regular expressions is crucial for all sailors from CNS fleet. A 3D crossword puzzle is available to enhance this skill.
May you have fair winds and following seas!
Download the regular cube crossword.
(MD5 checksum e0fccb92b8c46b80e75e350503a528ff)
Hints
Solution
The PDF document extracted from the archive contains the crossword with various regular expressions.
Note: Unfortunately the document is not very printer friendly 
This just needs to be solved manually, incrementally adding known characters until we know them all. The result looks as follows. We can easily spot the flag in the middle layer.
FOFOO
HELLO
OGTQM
HCATE
OVVWO
FWALO
PTHEB
CATCH
YTHQJ
HAYHO
FLAG{
NICE-
NAVY-
BLUE-
CUBE}
FOZGL
VCESP
GNETB
VDQPK
MVMPX
FHICE
MAYEM
GBYEQ
QERZQ
GQWSY