Examples of sarcasm in text would be the repetition of a letter, for example ‘naaaa’, this would indicate that the individual is using the repition of the letter ‘a’ to show that he’s last reply of the person he is having a text convosation with was obvious statement. Sarcasm is hard to conovel in a text convosation as  it is normally indicated in a spoken convostation with the tone of the speakers voice or a paralinguistic feature, for example as facial expression or a hand gesture.