If two squares with side lengths of 6 cm are put together to form a rectangle, what is the perimeter of the rectangle in cm?
两个边长是6厘米的正方形，拼成一个长方形，长方形的周长是多少厘米．
<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">12 + 6</gadget>
<output>18</output>

<gadget id="calculator">18 * 2</gadget>
<output>36</output>

<result>36</result>