"A 60-year-old man, with little hair on the head, almost bald

"A 60-year-old man, with little hair on the head, almost bald, with glasses and an expression of concentration. He is standing in front of a blackboard or whiteboard, explaining a physics concept with gestures and animated expressions. Wear a white or light-colored t-shirt with the text "Salty" printed in black and clear letters, without any other design or logo. The background is simple and neutral, to focus attention on the gentleman and his explanation. The lighting is soft and natural, no strong shadows."