The yellow line is twice as long as the red line, the red line is twice as long as the blue line, the blue line is twice as long as the black line, and the yellow line is twice as long as the black line.
黄线的长是红线的2倍，红线的长是蓝线的2倍，蓝线的长是黑线的2倍，黄线的长是黑线的多少倍．
<gadget id="calculator">2 * 2 * 2</gadget>
<output>8</output>

<result>8</result>