gistfile1.txt

>> module M
>>   x = 100
>>   define_method(:x=) {|v| x = v }
>>   define_method(:x) { x }
>> end
=> #<Proc:0x0000010102dfd0@(irb):4 (lambda)>
>> class A
>>   include M
>> end
=> A
>> class B
>>   include M
>> end
=> B
>> a = A.new
=> #<A:0x0000010103c030>
>> b = B.new
=> #<B:0x00000101039bf0>
>> a.x
=> 100
>> b.x
=> 100
>> a.x = 5
=> 5
>> b.x
=> 5
>>