...is this man solving a sudoku puzzle

Why?

• He reads the rules aloud
• He uses the board to visually confirm he understands the rules
• There isn't a moment where he is silent. He continues to speak aloud all of his thoughts, discoveries, skepticism, and joy when he discovers the next piece of this puzzle
• He makes his audience repeatedly aware - both verbally and visually - of the method by which he attempts to solve the next piece of this puzzle
• After finishing, he attempts and succeeds at finding an underlying pattern in the solution
• By watching him, the audience learned a lot...about him and about the rich complexity of the puzzle

He isn't 'coding'. But he is critically thinking, decoding, encoding, and ultimately demonstrating that he is highly competent.

Be like him in your next technical interview.