I found keeping track of 'self' in Ruby Classes to be exhausting, so I created this handy example illustrating when self changes, where instance variables are stored, and against which self methods are executed.

RubyScope.rb

class RubyScope
  # `self` is the RubyScope Class
  # (i.e. an Instance of RubyScope MetaClass)
  @variable_type = 'class instance variable'
  
  # Methods are defined in a class, but executd on an instance
  # Created on self: "RubyScope", Executed on self: "any instance of RubyScope"
  def initialize
    # `self` is an Instance of RubyScope Class
    @variable_type = 'instance variable'
  end
  
  def variable_type
    # `self` is an Instance of RubyScope Class
    @variable_type # returns `instance variable`
  end

  class << self
    # `self` is the MetaClass of RubyScope
    # (i.e. an Instance of a Class' MetaClass.. I think...)
    
    @variable_type = 'metaclass instance variable'
  
    # Methods are defined in a class, but executd on an instance
    # Created on self: "RubyScope's MetaClass". Executed on self: "RubyScope Class"
    def variable_type
      # `self` is the RubyScope class
      
      @variable_type # returns `class instance variable`
    end
    
    # Methods are defined in a class, but executd on an instance
    # Created on self: "RubyScope's MetaClass's Superclass". Executed on self: "RubyScope's MetaClass"
    def self.variable_type
      # `self` is the RubyScope's MetaClass
      
      @variable_type # returns 'metaclass instance variable'
    end
  end
end

Do you have an example usage of this?