This is a corner faceted tower on the very shore of Siverskoye Lake. It protrudes far beyond the line of the walls, for the convenience of flanking the fortress walls.
If you look at it from a distance, some of its asymmetry is striking. This is not because it was designed this way, the tower just is tilted to one side, like the famous building in the Italian city of Pisa. The building started tilting in the middle of the 19th century and continues to do it this day. Moreover, the tilt of the internal stone pillar with the lookout is not synchronized with the tilt of the walls, which is why the structure gets its bizarre appearance.