I will eventually answer your question.
However, I want you to know that the example which uses the word "trees" is more likey to make people feel happy than the example using the word "guns."
A large portion of the human population enjoys looking at living trees and touching living tree bark.
Reading a large number of examples of English phrases containing words like "gun", "weapon", "die", "blood", etc cetra is more likely to increase a readers risk of becoming clinically depressed in the future than if they read example using words without negative connotations.
Now, I will answer your question.
Ambiguities in the English language can somtimes be resolved by employing mathematical methods.
Let σ be the sentence, "There were trees on both sides of the street".
σ has almost the same meaning as the following mathematical statement:
Let s be a street.
By the definition of street, s has exactly two sides.
Denote the sides of street s as side x and side y such that x is distinct from y.
There are trees on x and there are trees on y.
The string "There were trees on each side of the street" has a meaning similair to the mathematical example provided above.
However, the string, "there were trees on either side of the street" is problematic.
It is more correct to write, "either there were trees on one side of the street or there were trees on the other side of the street"
If the error (noise factor) is small, then fluent users of the English language can discern what the meaning of a misspelled sentence is.
Suppose that the street under consideration has a West side and the street under consideration has an East side.
The following examples all have the same meaning:
- You can put the trees on either side of the street.
- You can put the trees on west side of the street or you can put the trees on the East side of the street.
- Either (you can put the trees on the west side of the street) or (you can put the trees on the east side of the street)
Most people limit the amount of time they spend thinking about it.
People guess what the meaning of sentences are within a reasonable degree of aproximation.