<!-- BEGIN COPY / PASTE -->
        // Example of using requestAnimationFrame for animations
        function animate() {
            // Animation logic here
            console.log("Animating...");
            requestAnimationFrame(animate);
        }
        requestAnimationFrame(animate);

        // Example of using event delegation
        document.querySelector("#parent").addEventListener("click", function(event) {
            if (event.target.matches(".child")) {
                console.log("Child element clicked:", event.target);
            }
        });

        // Example of using memoization
        const memoizedFactorial = (function() {
            const cache = {};
            return function factorial(n) {
                if (n in cache) {
                    return cache[n];
                } else {
                    if (n === 0) {
                        cache[n] = 1;
                    } else {
                        cache[n] = n * factorial(n - 1);
                    }
                    return cache[n];
                }
            };
        })();

        console.log(memoizedFactorial(5)); // Outputs: 120
        <!-- END COPY / PASTE -->