Describe an intelligent person you know

The most intelligent person I know is my classmate Zafar, with whom I studied at university. He's in his early twenties and is studying physics, and I met him on the first day of the course when we shared a desk.

He is good at a lot of things, but especially at mathematics and logic. He can solve complex problems in his head that take most of us several pages of calculations. He also speaks four languages, plays chess at a high level and is a self-taught programmer. At the same time, he is far from the stereotype of the lonely genius, as he's sociable and has many friends.

There are several reasons why I think he's intelligent. First, he learns incredibly quickly. When our professor introduces a new concept, Zafar grasps it almost immediately and is able to explain it in simpler terms to the rest of us. Second, he thinks very critically. He doesn't accept things just because they're written in a textbook; he asks why, and often finds an alternative method. Third, he's curious beyond the syllabus. He reads scientific articles for fun and discusses topics like space and artificial intelligence.

Another thing I admire is his humility. He never boasts about his marks, and he is always ready to help others, including me, with difficult assignments.

I believe his intelligence comes from a combination of natural ability and constant effort, since he studies for many hours. Being friends with him has certainly motivated me to challenge myself more in my own studies.