A rope 12 meters long is used to form the largest square against a wall. What is the area of the square?
用一根长12米的绳子围成一面靠墙的最大的正方形，这个正方形的面积是多少．
<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<result>16</result>