A kind of bacteria, every 1 minute, changes from the original 1 to 2, and after 4 minutes, this number is how many times the original.
一种细菌，每经过1分钟，就由原来的1个变成2个，经过4分钟后，这种数量是原来的多少倍．
<gadget id="calculator">2 / 1</gadget>
<output>2</output>

<gadget id="calculator">2 * 2 * 2 * 2</gadget>
<output>16</output>

<result>16</result>