Kiran stands in the center of a room with white walls, facing north. The room is square, and each wall has one window right in the center that is wide enough for a person to look through comfortably. To Kiran's left, on the west wall, Zurie is standing outside, trying to catch Kiran's attention through the window. Directly behind Kiran, to the south, is another window through which Amir can see Kiran's back. Amir is hoping to communicate with Kiran but does not want to alert Zurie of his presence. To complicate matters, on the east wall, positioned exactly opposite Zurie, Nia has climbed a tree and is now at eye level with the eastern window. Nia is also trying to get Kiran's attention without Zurie noticing.

Kiran is wearing a hat with a wide brim that covers the eyes and ears when viewed from the side. Kiran has not noticed Nia yet and is unaware of Amir's presence behind. At this point, Kiran is focused on a book held just below eye level, obscuring the lower half of the face from the front view. Kiran's peripheral vision is also partially blocked by the hat's brim.

Taking into consideration the positioning of the three individuals on the outside and Kiran's current engagement with the book as well as the hat's brim, describe what Kiran, Zurie, Nia, and Amir can see at this moment. Also, if any of the observers outside, Zurie, Nia, or Amir, change their vertical position, how would that affect what they can see? Assume there are objects such as a bench, tree, and a small ladder available outside for the observers to change their vertical positions.
Kiran, focused on the book and facing north, has limited visibility. Kiran's view is confined to what is directly ahead due to the book, and the peripheral vision is further restricted by the wide brim of the hat. Zurie, who is standing outside the west window trying to catch Kiran's attention, cannot be seen by Kiran due to the angle and the hat's brim blocking the side view. Kiran may, consciously or unconsciously, only be able to see the direct view through the northern window, and even that only above the book.

Zurie, stationed to the west of Kiran and at ground level, has a clear line of sight to Kiran's profile. Zurie can only see the side of Kiran's head and the hat's brim, as well as the upper body as Kiran is facing north and oblique to Zurie's position. The window's positioning does not allow Zurie to see much beyond what's directly in line with the window pane.

Nia, who is in the tree level with the east window, also has a clear view of Kiran's side but from the opposite side compared to Zurie. However, given the hat's brim, Nia can only see one side of Kiran's face and part of the body, similar to what Zurie can see. Since Kiran's attention is on the book below eye level and is not facing east, Nia does not catch Kiran's attention.

On the other hand, Amir, who is behind Kiran to the south, can see Kiran's back and the hat but does not have a view of Kiran's face or the book. Amir's perspective includes a full view of Kiran's backside, from head to heel, through the southern window.

If Zurie decides to increase elevation by standing on the bench, Zurie's angle of view would change to see more of the top of Kiran's hat and possibly a slight glimpse of the book if it's held high enough. However, Kiran's face would still be obscured due to the hat's brim and book. If Zurie climbed the ladder, Zurie might catch a glimpse of Kiran's face from above if the book is low enough, but this would also risk being seen by Nia and Amir due to the increased profile and movement.

If Nia climbs higher in the tree, the angle would allow Nia to potentially see the top of Kiran's head and possibly down into the book depending on the height and the angle. However, the brim of the hat is likely to still obscure the view of the face. A higher position makes it likelier for Zurie and Amir to notice Nia due to the movement and change in position.

For Amir, changing vertical position has less of an impact unless Amir goes higher than the level of the window. If Amir stood on the ladder, the view would mainly be the same, only slightly more on top of Kiran's head, which does not change what Amir can see in terms of Kiran's activity with the book or face.

Each observer's sightlines are dictated by their positions in relation to Kiran, the room's geometry, and obstacles like the hat's brim and the book that Kiran is holding. Moving vertically changes the angles moderately but does not drastically change the information each person can glean due to Kiran's attire and position.