A rectangle is formed by combining two squares with side lengths of 2 cm. What is the perimeter of this rectangle?
用两个边长为2厘米的正方形拼成一个长方形．这个长方形的周长是多少？
<gadget id="calculator">2 + 2</gadget>
<output>4</output>

<gadget id="calculator">4 + 2</gadget>
<output>6</output>

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<result>12</result>