Xiaoqiang used chess pieces to form a hollow square matrix with 11 pieces on each side, a total of 2 layers. How many chess pieces are used in this square array?
小强用棋子排成了一个每边11枚的中空方阵，共2层，求这个方阵共用多少枚棋子？
<gadget id="calculator">11 * 4</gadget>
<output>44</output>

<gadget id="calculator">44 - 4</gadget>
<output>40</output>

<gadget id="calculator">11 - 2</gadget>
<output>9</output>

<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<gadget id="calculator">36 - 4</gadget>
<output>32</output>

<gadget id="calculator">40 + 32</gadget>
<output>72</output>

<result>72</result>