You all know the game minesweeper i guess so i don't have to explain the rules?
I have 4 mines in this area:
Code:
----
-1--
----
-1--
----
----
And made a tester and found the approximative chance of hiting a mine at each square:
Code:
172‰ 173‰ 173‰ 236‰
173‰   0‰ 173‰ 239‰
 44‰  44‰  44‰ 237‰
173‰   0‰ 173‰ 237‰
173‰ 173‰ 174‰ 238‰
236‰ 237‰ 237‰ 237‰
If you add them up you get 4, the amount of mines, also there are 4 areas with different chances of hitting a mine:
Code:
AAAD
ABAD
CCCD
ABAD
AAAD
DDDD
where each areas chance is
A:172‰
B:0‰
C:44‰
D:237‰

How do you do this mathematically?