So I noticed the fourth note of most strings is a semi-tone below the next string.
For example, G♯ (4th note) on the low E string is a semi-tone below the next string, which is A; the C♯ on the A string is a semi-tone below the next string, which is D.
This seems to be the pattern but it is not the case on the G string's B (4th note), which is not a semi-tone below the next B string,
I was wondering why the choice to tune it this way?