Basic Box Pattern Upper Bound

The blue cells contain one mine

The green cells contain one mine

The 2x2 box contains 2 mines in total

One of these mines is in the yellow cells

The remaining mine is therefore in the red cells

The 5 needs four mines, one is in the red cells. The three other mines must go into the three red-crossed cells

The 3 sees a red crossed cell, and the green cells, so the lime crossed cells are safe

The 3 sees a red crossed cell, so the green crossed cells are safe

The first and currently only upper bound (proves mines rather than cells) that i’ve found

Broader Image: 1nAK52c

Full game: See “Game Records of Rare Patterns”

Another interesting thing about this example is the amount of resulting safe cells, 4 is quite high

Additional images