This is a delight to play with; thanks for sharing!
One slight UX suggestion: Consider a "start" button before making the camera request. Permission prompts are blocking modals on Safari (unlike Chrome where they're a pop-over from the toolbar), so the user doesn't necessarily have context if it's on page load!
One slight UX suggestion: Consider a "start" button before making the camera request. Permission prompts are blocking modals on Safari (unlike Chrome where they're a pop-over from the toolbar), so the user doesn't necessarily have context if it's on page load!