Merging class attributes up the tree

gistfile1.rb

class Ancestor
  @props = {a:1, b:1, c:1}
  def self.merged
    (ancestors[1].respond_to?(:merged) ? ancestors[1].merged : {}).merge(@props)
  end
end

class Child < Ancestor
  @props = {a:2}
end

class GChild < Child
  @props = {c:3}
end

p GChild.merged 
#=> {:a=>2, :b=>1, :c=>3}