In 2019, artist Sam Cox bought a mansion in the English countryside. Stripping it bare and painting all the walls white, he then spent two years covering every inch of it with black marker doodles—whimsical, surreal scribbles dubbed “Spaghetti Graffiti.” A stop-motion film capturing this endeavor propelled “Mr. Doodle” to global fame. What began as a total and imaginative artis...