I did a side project that helps with comparisons, but in a rather different way (e.g. how many African elephants does something weigh). Not as slick as this site, but someone might find it useful:

http://howmanyelephants.co.uk/

    (function() {
        let direction = 'right'; // Start by going right
        let intervalId;

        function getCurrentAnimalName() {
            const animalDiv = document.querySelector('.animal-name');
            return animalDiv ? animalDiv.textContent.trim() : '';
        }

        function pressKey(keyCode) {
            const event = new KeyboardEvent('keydown', {
                key: keyCode === 37 ? 'ArrowLeft' : 'ArrowRight',
                keyCode: keyCode,
                code: keyCode === 37 ? 'ArrowLeft' : 'ArrowRight',
                which: keyCode,
                bubbles: true
            });
            document.dispatchEvent(event);
        }

        function autoScroll() {
            const currentName = getCurrentAnimalName();
            
            if (direction === 'right') {
                pressKey(39); // Right arrow
                
                if (currentName === 'Pando Clone') {
                    console.log('Reached Pando Clone, switching to left');
                    direction = 'left';
                }
            } else {
                pressKey(37); // Left arrow
                
                if (currentName === 'DNA') {
                    console.log('Reached DNA, switching to right');
                    direction = 'right';
                }
            }
        }

        // Start the interval
        intervalId = setInterval(autoScroll, 3000);
        
        // Log start message and provide stop function
        console.log('Auto-scroll started! To stop, call: stopAutoScroll()');
        
        // Expose stop function globally
        window.stopAutoScroll = function() {
            clearInterval(intervalId);
            console.log('Auto-scroll stopped');
        };
    })();

Star Size Comparison 3, simply a stunning visualization.