There is a rectangular fountain with a length of 6 meters and a width of 4 meters. What is the perimeter of the fountain?
有一个长方形的喷水池，长是6米，宽4米，这个喷水池的周长是多少米？
<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<result>20</result>