Is there any more explanation behind the staggered collapse?
Consider the example:
_ _ x _
_ X _ _
x _ x x
_ _ x _
Here, the capital X has just been murdered, so the question results do you collapse horizontal or vertically as you will get different boards with each:
_ _ x _
_ _ _ _
_ _ x _
or
_ _ _
_ _ _
x _ x
_ _ _
The need to line these up gets around this issue...
Consider the example:
_ _ x _
_ X _ _
x _ x x
_ _ x _
Here, the capital X has just been murdered, so the question results do you collapse horizontal or vertically as you will get different boards with each:
_ _ x _
_ _ _ _
_ _ x _
or
_ _ _
_ _ _
x _ x
_ _ _
The need to line these up gets around this issue...