Recursive workflows
There are scenarios where you may need to iterate over a list of items and execute a workflow for each of those items. For these scenarios, you can create recursive workflows. A recursive workflow is a workflow that calls itself (conditionally). For example, for a countdown timer you could create a workflow that decreases a variable, waits for some time and then calls itself again until the target value of 0 is reached.
Warning
Make sure you have a break condition, sleep timers or other measures in place so that the workflow does not call itself infinitely and cause an endless loop, which may cause a blue screen of death.