Although this appears to be amusing, the child is apparently trying to tell someone he is bored. If he is a bright child and the work is too easy, he will become a major behavior problem. Without offending, you might suggest the teacher find logic problems, problem solving, independent research projects, etc. that he could work on and share with the class. He needs to be challenged asap!
I taught gifted and talented for over 20 years. Contrary to the popular opinion of it being a cushy job, I learned immediately that my students had to be challenged. They were too bright to tolerate being bored. Those are the kids who DO have discipline problems at times when they are left to their own entertainment. Their parents think they're precious and adorable. They're thrilled they are smart and sometimes create little monsters by telling the kid how bright and smart he is. From the teacher's point of view, they must learn what it's like to have to study, to not always know the correct answer and every now and then have that little uncomfortable feeling in their tummy that tells them they don't know how to do this. If not, and they are not learning, and you can bet there will be problems.