jjj,
What shape is the image produced by a piece of film or a sensor? A rectangular one. So that is what you need to consider when taking photos, not the just the shape of the subject.
1. Frame aspect is independent of focal length
2. Frame aspect can be square
3. If Kirk referred to the frame, why did he refer to "rectangles" - plural? A typographic error seems unlikely (refer below to my response to Manoli).
4. If Kirk referred to the frame, why did he associate a "wider lens" with fewer "objects", which contradicts Bart's comment that "...a wider angle of view tends to show more objects..."?
Manoli,
A frame consisting of four straight sides and four right angles with unequal adjacent sides...
By substituting the word "frame", Kirk's comment becomes:
A wider lens will lead sooner to the realization that one is photographing [the] frame, not objects...
Does the above make sense to you?
A frame consisting of four straight sides and four right angles with unequal adjacent sides...
Three right-angles are sufficient to define a rectangle, according to your definition.
stamper,
I think he is trying to be provocative?
Not at all. Kirk's comment makes no sense to me, so I asked for clarification.