His experimentation started with using a laser pointer to send a beam of light through a glass of milk (an experiment I recreate below).

他开始试验用激光教鞭派手电光透过一杯牛奶(我再造一个实验段)。

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For example, in a word processor, the pointer takes the I-beam shape while it's over the text and changes to an arrow when it's over a tools palette.

例如，在字处理程序中，光标在文本位置会呈现i字型，在工具栏会呈现箭头形状。

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