Ruby mind twister

mind_twister.rb

# 6. The superclass of the singleton class of an object is the object's class.
#    The superclass of the singleton class of a class is the singleton class
#    of the class's superclass.

class Person; end
p = Person.new
puts p.singleton_class.superclass == p.class #=> true
puts Person.singleton_class.superclass == Person.superclass.singleton_class #=> true