Forgive me if someone else has posted about this before, but I would like to note another seven hidden into the game design of all of the Marathon games.
When you first start the game, you have a pistol and two fists. Three. Interesting. We have 3 spare clips of pistol ammo. Another three. 3+3=6. But wait - we also have a clip of ammo already in our pistol. 6+1=7
Let's go over it again:
Three weapons, if you count each fist as being a separate weapon. 3
Three spare ammo clips. 3
One ammo clip in our pistol already. 1
3+3+1=6+1=7
Coincidence? I think not! ;)
Cheers,
PerseusSpartacus