If the radius of the bottom of the cylinder is doubled, and the height is also doubled, the volume of the cylinder will be doubled.
圆柱底面半径扩大2倍，高也扩大2倍，这个圆柱的体积就扩大多少倍
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<result>8</result>