The Tower Shandune is the center of the Kingdom of Winterfell. It is used for sell via vendors, smithing, but more interestingly, as a place for the kingdom to meet.

Upon the roof they have arranged a set of tables and chairs in a large rectangle, with a lantern upon each table. Then as the meeting proceeds and points of interest are brought up, the members use the lanterns to vote.

This makes it easy for the leaders to count lighted lanterns as yes votes, and unlit as no votes. Much quicker and easier than vocal roll calls.

The tower also boasts a fairly extensive library. I just hope that the unnamed ones soon make it possible to lock those books down inside their book cases so that such treasured works do not have to constantly be re-copied.