Understanding the Eigenclass in less than 5 minutes

class Greeting def self.hello 'hello world!' end def self.eigenclass class << self self end end end Greeting.eigenclass # => #<Class:Greeting> Greeting.eigenclass.name # => nil Greeting.singleton_methods # => [:hello, :eigenclass] Greeting.eigenclass.instance_methods(false) # => [:hello, :eigenclass] 

class << self