If you have two rectangles with a length of 4 cm and a width of 2 cm and put them together to form a square, what is the perimeter of the square in cm?
有两个长4厘米，宽2厘米的长方形，把他们拼成一个正方形，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>