中文说明：
示例-FFT的三维干图对于示例，在复平面上单位圆周围的点处计算快速傅里叶变换。因此，将单位圆周围的图可视化是很有趣的。计算单位圆。
English Description：
Example - three dimensional stem of FFT for example, the fast Fourier transform is calculated at a point around the unit circle on the complex plane. Therefore, it is interesting to visualize the graph around the unit circle. Calculation unit: circle