invisiwill

class Array
  def flatten_nested_numeric_array
    self.inject([]) do |new_array, element|
      new_element = element.class == Array ? element.flatten_nested_numeric_array : element
      new_array += new_element if new_element.class == Array
      new_array << new_element if new_element.class == Fixnum
      new_array
    end
  end