module Mod
  def foo(x)
    x**2
  end
end
module Mod2
  def foo(x)
    x*2
  end
end

class A
  include Mod
  def foo(x)
    super(x) + 1
  end
end
A.new.foo(5) == 26 # true

class A
  include Mod2
  def foo(x)
    super(x) + 1
  end
end
A.new.foo(5) == 11 # true

class A
  include Mod
  def foo(x)
    super(x) + 1
  end
end
A.new.foo(5) == 26 # false. Is 11

class A
  include Mod
  def foo(x)
    super(x) + 1
  end

  include Mod2
  def foo(x)
    super(x) + 1
  end

  include Mod
  def foo(x)
    super(x) + 1
  end
end

class A
  include Mod
  def foo(x)
    super(x) + 1
  end
end
A.new.foo(5) == 26 # true

class A
  include Mod2
end
A.new.foo(5) == 11 # true

class A
  include Mod
end
A.new.foo(5) == 11