This class provides an enumeration function to have the object which I added tree information to in an argument. The instance receives an enumerable object and provides #each and #each_method. The #each method calls a block in an argument in own. The #each_method method calls the method of an object appointed own in an argument. I have the information of the object equal to the ancestors in own and front and back and hierarchy structure, and a block and the argument handed to a method maintain the state flag in the enumeration again. It is necessary to appoint the information about the descendant in the hierarchy structure in a block - a method explicitly. When the #into method receives an enumerable object, and a block is not exhibited, a block - a method is used recursively. This class provides a function to enumerate it, but it is not the object which it can enumerate.