The Queue element is a simple for-loop to iterate through the workflow.

The Queue is draged into a Group and connected with in- and outputs of the logics. In the properties window the maximal number of iterations is set.

Properties Window

At first the Queue takes the input from the Import logic and passes it to BoxManipulation. In the second round the output IO from the logic BoxManipulation is passed by the Queue to become the input IO for the same logic. Here the maximal iteration number was set to 5.
Input Description
FirstInput Input, which starts the Queue
SecondInput Input to close the Queue
Output Description
FirstOutput Output of the i-th run of the Queue