1675 works like this:
1st year = small letter and graduation numerals
2nd year = large letter
3rd year = chevron
4th year = inverted large letter and 4 year patch
Letter is determined by school (We are up to 5 different schools now

)
If a student did not join as a freshman they can be bumped up 1 year in the progression for extreme circumstances (excluding 4-year patch).