# File lib/core/facets/array/step.rb, line 18
  def step(n) #:yield:
    if block_given?
      ((n - 1)...size).step(n).each do |i|
        yield(fetch(i))
      end
    else
      Enumerator.new(size / n) do |y|
        ((n - 1)...self.size).step(n).each { |i| y << fetch(i) }  
      end
    end
  end