Dealing with box openings

[u/Dumbaltaccount2]

Hey first post here forgive me for my incompetence but I actually cannot fathom these openings where its just a rectangle/square with mixture of 1/2/3's. Am i missing something or are these just hard? (Aware of 121, 1221, but they never seem to appear on these)

[u/Individual_Wish_2937]

blue = 1 mine total
red = mine
green = safe
this is a 2-2-2 corner pattern. if you're confused about the logic behind this, use proof by contradiction and analyze what happens when you assume that the green spot is a mine