What [software] must not do is not the inverse of what it must do. .
![What [software] must not do is not the inverse of what it must do. .](http://cdn.quoteddaily.com/images/nancy-leveson/what-software-must-not-do-is-not-the-inverse-of-what-it-must-do-.jpg)
What [software] must not do is not the inverse of what it must do. .