Role

Keith's eyes were drilled directly into the keys of the keypad. Then his thoughts drifted. 

There should be some meaning to these numbers and the amount of dots each one has. What does it stand for? Because if its meaningless, then what's the use of replacing the original numbers on the book spine and then putting dots below it? 

It's too well detailed and lots of effort if all of this is just a prank.

"Feel free to check whatever information you want." Lexi's voice drowned out from the staircase to the right. Keith can hear her retreating steps as she went upstairs. He ignored her and focus more on the dotted numbers. 

….

Fifteen minutes later, Keith is still staring at the numbers. Not making any sense out of it. 

….

Thirty minutes later, Keith still could not figure it out. 

….