1
2

rows_in_order = (0..7).to_a
rows_in_order.reverse! unless side == :white

1
2
3
4

require "set"

pools = {1 => [1,2,3], 2=> [3,4,5], 3=> [5,6,7]}  
...

1
2
3
4

require "rubygems"
require "facets/enumerable/probability"

...