Check out Johannes de Groot's haircuts throughout his career:
Johannes de Groot had various hairstyles during his lifetime. He became famous as a world-class mathematician, topologist and university teacher. However, the Dutch mathematician was particularly known for his unusual looks and his delightful personality. Before his tragic demise at the age of 58 he was often in the spotlight of the press due to his marvelous hair. Check out Johannes de Groot's former haircuts right here: