Each time use one of red, green, blue, and yellow to color 4 squares of different sizes, how many different ways can there be in total?
每次用红、绿、蓝、黄中的一种颜色分别给4个不同大小正方形涂色，一共可以有多少种不同的涂法．
<gadget id="calculator">4 * 4 * 4 * 4</gadget>
<output>256</output>

<result>256</result>