There is a square iron sheet. After cutting out a square with a side length of 2 cm from the four vertices, the remaining part is just welded into a square iron sheet box without a cover. What is the area of the original square in square centimeters?
有一块正方形铁皮，从四个顶点分别剪下一个边长2cm的正方形后，所剩部分正好焊成一个无盖的正方形铁皮盒，原来正方形的面积是多少平方厘米？
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">2 + 4</gadget>
<output>6</output>

<gadget id="calculator">6 * 6</gadget>
<output>36</output>

<result>36</result>