Use 3 squares with a side length of 3 decimeters to form a large rectangle. What is the perimeter of the rectangle?
用3个边长3分米的正方形拼成一个大的长方形，拼成的长方形的周长是多少分米？
<gadget id="calculator">3 + 3 + 3 + 3</gadget>
<output>12</output>

<gadget id="calculator">12 * 2</gadget>
<output>24</output>

<result>24</result>