Zhang Ming surrounds a square with a wire 16 cm long, what is the area in square centimeters?
张明用一根长16厘米的铁丝围正方形，面积是多少平方厘米．
<gadget id="calculator">16 / 4</gadget>
<output>4</output>

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

<result>16</result>