Conway's Game of Life in Ruby

conway.rb

class Life
  attr_reader :live_cells

  def initialize(live_cells)
    @live_cells = live_cells
  end

  alias :to_a :live_cells

  def next_generation
    next_cells = alive_neighbors.each_with_object([]) do |(cell, neighbors_count), next_cells|
      alive = @live_cells.include? cell
      next_cells << cell if Life.alive_next?(neighbors_count, alive)
    end
    Life.new next_cells
  end

  def alive_neighbors
    @live_cells.each_with_object(Hash.new(0)) do |(x, y), neighbors|
      neighbor_cells = Array(x-1..x+1).product(Array(y-1..y+1)) - [[x, y]]
      neighbor_cells.each {|cell| neighbors[cell] += 1 }
    end
  end

  def self.alive_next?(neighbors_count, alive=true)
    neighbors_count == 3 or alive && neighbors_count == 2
  end
end