class Dog
    def speak
        woof
    end
end

def woof
    if @dog_generic == nil
        puts "@dog_generic isn't scoped when .woof is called from a class method!\n"
    else
        puts "@dog_generic is scoped when .woof is called from the global scope. See:\n" + @dog_generic
    end
end

@dog_generic = "Woof!"
lassie = Dog.new
lassie.speak #=> @dog_generic isn't scoped when .woof is called from a class method!\n

woof #=> @dog_generic is scoped when .woof is called from the global scope. See:\nWoof!