This is a Ruby tree! It shows every object from the Ruby Programming Language in a tree format.

include? 

        # Module.include?

(from ruby core)
---
    mod.include?(module)    -> true or false

---

Returns `true` if *module* is included or prepended in *mod* or one of
*mod*'s ancestors.

    module A
    end
    class B
      include A
    end
    class C < B
    end
    B.include?(A)   #=> true
    C.include?(A)   #=> true
    A.include?(A)   #=> false

This is MURDOC! A Ruby documentation browser inspired by Smalltalk-80. It allows you to learn about Ruby by browsing through its class hierarchies, and see any of its methods.