Comment by randerson
The quickest solution, assuming learning from the problem isn't the priority, might be to replace the entire chain of lights without testing any of them. I've been part of some elusive production issues where eventually 1-2 team members attempted a rewrite of the offending routine while everyone else debugged it, and the rewrite "won" and shipped to production before we found the bug. Heresy I know. In at least one case we never found the bug, because we could only dedicate a finite amount of time to a "fixed" issue.
> The quickest solution, assuming learning from the problem isn't the priority, might be to replace the entire chain of lights without testing any of them.
So as a metaphor for software debugging, this is "throw away the code, buy a working solution from somewhere else." It may be a way to run a business, but it does not explain how to debug software.