State of the art (sometimes cutting edge) ： the level of development (as of a device, procedure, process, technique, or science) reached at any particular time usually as a result of modern. 在程序代码中似乎很好区分：因为状态机（state machine）、 状态迁移图 （state transition diagram）都是明确的 state，所以如果「状态」的有效值之间可以搞出类似状态迁移.
Restore Energy Levels at Wilbur Pritt blog
