cat_eigens.rb

irb(main):054:0> class Cat
irb(main):055:1>   def eigen
irb(main):056:2>     class << self
irb(main):057:3>       self
irb(main):058:3>     end
irb(main):059:2>   end
irb(main):060:1> end
=> nil
irb(main):061:0> c1 = Cat.new
=> #<Cat:0x1017562d0>
irb(main):062:0> c2 = Cat.new
=> #<Cat:0x1017526d0>
irb(main):063:0> c1.class
=> Cat
irb(main):064:0> c1.eigen
=> #<Class:#<Cat:0x1017562d0>>      <-- An instance of class Cat, subtyped from class Class
irb(main):065:0> c2.class
=> Cat
irb(main):066:0> c2.eigen
=> #<Class:#<Cat:0x1017526d0>>
irb(main):067:0> c1.class == c2.class
=> true
irb(main):068:0> c1.eigen == c2.eigen
=> false
irb(main):069:0> c1.kind_of? Cat
=> true
irb(main):070:0> c1.kind_of? c1.eigen
=> true
irb(main):071:0> c1.kind_of? c2.eigen
=> false
irb(main):072:0> c2.kind_of? Cat
=> true