How can objects be dynamically added to object instances in PHP classes?

In PHP, objects can be dynamically added to object instances in classes by using the magic method `__set()`. This method allows you to dynamically set properties on an object that have not been declared in the class definition. By implementing `__set()`, you can handle the dynamic addition of properties and their values at runtime.

class MyClass {
    private $data = [];

    public function __set($name, $value) {
        $this->data[$name] = $value;
    }

    public function __get($name) {
        return $this->data[$name];
    }
}

$obj = new MyClass();
$obj->dynamicProperty = "Dynamic Value";
echo $obj->dynamicProperty; // Output: Dynamic Value