+----------------+
|     Shape      |
+----------------+
| + getArea(): double |
+----------------+
         ^
         |
  +------+------+------+
  |             |      |
+--------+  +----------+  +----------+
| Circle |  | Rectangle|  | Triangle |
+--------+  +----------+  +----------+
| - radius: double |  | - length: double |  | - base: double |
| + Circle(radius: double) |  | + Rectangle(length: double, width: double) |  | + Triangle(base: double, height: double) |
| + getArea(): double |  | + getArea(): double |  | + getArea(): double |
+--------+  +----------+  +----------+

+----------------+
|   ShapeUtil    |
+----------------+
| + printArea(shape: Shape): void |
+----------------+
         |
         v
+----------------+
|     Shape      |
+----------------+