Tower entry puzzle

The Tower entry puzzle is a puzzle in Obduction that grants access to the Tower and eases travel between northern Hunrath, southern Hunrath, and the western side of the Wall. The additional power puzzle must be completed to understand the provided clues, but is not necessary to actually finish the puzzle. It consists of three main parts.

Community Center
Go to Farley's Community Center. Find the projector screen in the corner of the main room. (It is next to the screen with the map of Hunrath on it.) Pull down the screen until it is most of the way down the chalkboard, revealing what may be either the number "15" or the word "IS" with four small lines in the corners. Find the slide projector on the Lazy Susan. If the projector is off, turn it on by flicking the yellow switch behind it. Change the slide so that it projects a grid of dots with four small lines instead of a small circle. Using the Lazy Susan, superimpose the grid of dots onto projector screen you pulled down. It is aligned correctly when all of the small lines form X's.

Gas Station
Go inside the Gas Station. Find the cash register attached to the Villein control panel. Input the clue from the Community Center, and press the blue button above the panel. The panel will self-correct into this Villein number: The cash register will display it's value in Arabic numerals: 406.

Western Wall
Leave the Gas Station and pass through the Trainyard, exiting through the building in the back. Continue forward until the back door to the Community Center in on your right. Turn left and head forward until the path splits. Turn right and continue forward until you pass through the Cell membrane. Walk forward and left until you reach the swing bridge. Walk in the opposite direction of the bridge, entering a wooden structure until you pass through the Cell membrane again. Continue along the Wall until you reach the western entrance of the Tower. Input "406" into the keypad, and the door will automatically slide open.