Xiao Ming baked two cylindrical cakes with a bread machine. Each cake has a bottom diameter of 12 cm and a height of 4 cm. Help him design the packaging box and calculate how many square centimeters of packaging materials are needed?
小明用面包机烤了两个圆柱形蛋糕，每个蛋糕底面直径12厘米，高4厘米，帮他设计包装盒，并计算所需包装材料多少平方厘米？
<gadget id="calculator">12 * 2 * 12</gadget>
<output>288</output>

<gadget id="calculator">12 * 2 * 4</gadget>
<output>96</output>

<gadget id="calculator">12 * 4</gadget>
<output>48</output>

<gadget id="calculator">288 + 96 + 48</gadget>
<output>432</output>

<gadget id="calculator">432 * 2</gadget>
<output>864</output>

<result>864</result>