The present disclosure provides an innovative circuit structure for control insertion into a multiple-word wide data stream. The control-insertion circuit structure is advantageously scalable as the data width increases. An exemplary implementation of the control-insertion circuit structure includes a multiple-layer shifting circuit. The multiple-layer shifting circuit has some similarities with a barrel shifter. However, unlike a barrel shifter, the multiple-layer shifting circuit moves data words in both directions and moves portions of the data to create spaces or holes in the data (rather than moving the entire width as a barrel shifter does). The output of the multiple-layer shifting circuit is a “swiss-cheese-like” structure of data, where the spaces or holes in the data are available for control insertion. Other features, aspects and embodiments are also disclosed.