Assassin's Creed II HELP - Truth File 12

Can someone please help me out? I'm trying to finish the puzzle for truth file 12 (the Edison one) and I'm on the final part where I need to align the wheel and enter the password and the choices to line up on the wheel are ., .., I, I., II, II., II.., and III. and the advice says that theres a pattern, and its a base 3 number system. I don't know what any of this means but please help me. Thanks so much

Puzzle 12 is The Titans of Industry puzzle...if that is the one you are stuck on then perhaps I can help. There are three puzzles for number twelve and the last one is 139 (on top) and on the bottom, it's two lines and a dot, three lines, and a line and two dots.

Go here and scroll down a bit and u will see "Puzzle solutions"

thanks so much