There are two rectangles with a length of 4 cm and a width of 2 cm. If you put them together to form a square, what is the perimeter of the square in cm?
有两个长方形，长都是4厘米，宽都是2厘米，如果把它们拼成一个正方形，这个正方形的周长是多少厘米．
<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<result>16</result>