Perhaps you're thinking of a specific programming concept or pattern that uses loops in a particularly complex or unusual way.
If you can provide more context or information about what you're referring to, I can help you identify what you're looking for.
For example:
* What specific programming task are you trying to accomplish?
* What code snippet or description of the loop's behavior do you have?
* What programming languages are you familiar with?
Knowing these details will help me understand your question better and provide a more accurate answer.