TIL some people have never heard of foreshadowing.
What if, and this is just a huge if, the "perfect sphere" analogy is a hint towards inner turmoil explored later on by the characters? Almost as if our protagonist retreats from relationships because of her internalised vulnerability caused by family trauma or something 🤔. Nope, must be bad writing /s.
Incidentally, I also think detective fiction are all crap because authors keep putting in these unrelated details called "clues" for the readers. No way those "clue" things can be relevant later on.