4 ways to define class methods

gistfile1.rb

# most people do
class Foo
  def self.method1
    puts "method1"
  end
end

# or this
class Foo
  class << self
    def method2
      puts "method2"
    end
  end
end

# this was new to me, but it makes sense
class Foo
  def Foo.method3
    puts "method3"
  end
end

# i don't know if this is supposed to work, but it does. no need to open the class to define something on it
def Foo.method4
  puts "method4"
end

# they all work

Foo.method1 # => "method1"
Foo.method2 # => "method2"
Foo.method3 # => "method3"
Foo.method4 # => "method4"