Tibetan Singing Bowl

https://youtu.be/oob8zENYt0g

The orbiting perturbation causes wild fluctuations

https://www.iop.org/news/11/july/page_51352.html

https://iopscience.iop.org/article/10.1088/0951-7715/24/8/R01

![](https://imagizer.imageshack.com/img924/7735/QDk7RF.gif)