diff --git a/Roadmap/27 - SOLID OCP/php/miguelex.php b/Roadmap/27 - SOLID OCP/php/miguelex.php
new file mode 100644
index 0000000000..91c555d251
--- /dev/null
+++ b/Roadmap/27 - SOLID OCP/php/miguelex.php	
@@ -0,0 +1,150 @@
+<?php
+
+// Ejercicio Básico
+
+class Rectangle {
+    public $width;
+    public $height;
+
+    public function __construct($width, $height) {
+        $this->width = $width;
+        $this->height = $height;
+    }
+}
+
+class Circle {
+    public $radius;
+
+    public function __construct($radius) {
+        $this->radius = $radius;
+    }
+}
+
+class AreaCalculator {
+    public function calculate($shapes) {
+        $area = 0;
+        foreach ($shapes as $shape) {
+            if ($shape instanceof Rectangle) {
+                echo "\nEl area del rectangulo es: ". $shape->width * $shape->height;
+            } elseif ($shape instanceof Circle) {
+                echo "\nEl area del circulo es: ". pi() * $shape->radius * $shape->radius;
+            }
+        }
+    }
+}
+
+$shapes = [
+    new Rectangle(5, 10),
+    new Circle(7)
+];
+
+echo "Ejercicio básico (sin cumplir OCP)";
+$calculator = new AreaCalculator();
+echo $calculator->calculate($shapes);
+
+// El problema de esta solución es que si ahroa creamos una clase triangle (por ejemplo) y queremos calcualr su área, debemos modificar AreaCalculator para tener en cuenta la nueva forma
+
+interface Shape {
+    public function area();
+}
+
+class Rectangle2 implements Shape {
+    private $width;
+    private $height;
+
+    public function __construct($width, $height) {
+        $this->width = $width;
+        $this->height = $height;
+    }
+
+    public function area() {
+        return $this->width * $this->height;
+    }
+}
+
+class Circle2 implements Shape {
+    private $radius;
+
+    public function __construct($radius) {
+        $this->radius = $radius;
+    }
+
+    public function area() {
+        return pi() * $this->radius * $this->radius;
+    }
+}
+
+class AreaCalculator2 {
+    public function calculate($shapes) {
+        
+        foreach ($shapes as $shape) {
+            echo "\nEl área de la forma es: ". $shape->area();
+        }
+    }
+}
+
+$shapes = [
+    new Rectangle2(5, 10),
+    new Circle2(7)
+];
+
+echo "\nEjercicio básico (cumpliendo OCP)";
+$calculator = new AreaCalculator2();
+echo $calculator->calculate($shapes);
+
+// Con este enfoque, la clase Triangle tendría su propia definición de como calcular el área y AreaCalculator2 no se tendría que modificar
+
+// Ejercicio Extra
+
+interface Operation {
+    public function calculate ($a, $b);
+}
+
+class Sum implements Operation {
+    public function calculate($a, $b) {
+        return $a + $b;
+    }
+}
+
+class Substract implements Operation {
+    public function calculate($a, $b) {
+        return $a - $b;
+    }
+}
+
+class Multiply implements Operation {
+    public function calculate($a, $b) {
+        return $a * $b;
+    }
+}
+
+class Divition implements Operation{
+    public function calculate($a, $b) {
+        return $a / $b;
+    }
+}
+
+class Calculator {
+    public function calculate($operation, $a, $b) {
+        return $operation->calculate($a, $b);
+    }
+}
+
+$calculator = new Calculator();
+echo "\nEjercicio extra";
+echo "\nLa suma de 5 y 10 es: ". $calculator->calculate(new Sum(), 5, 10);
+echo "\nLa resta de 5 y 10 es: ". $calculator->calculate(new Substract(), 5, 10);
+echo "\nLa multiplicación de 5 y 10 es: ". $calculator->calculate(new Multiply(), 5, 10);
+echo "\nLa división de 5 y 10 es: ". $calculator->calculate(new Divition(), 5, 10);
+
+// A continuación vamos a añadir la operación potencia.
+
+class Power implements Operation {
+    public function calculate($a, $b) {
+        return pow($a, $b);
+    }
+}
+
+echo "\nLa potencia de 5 y 10 es: ". $calculator->calculate(new Power(), 5, 10);
+
+// Como vemos, no hemos tenido que modificar nada en la clase Calculator
\ No newline at end of file