Let ‘s assume each order requires a bleed. This means that a double cut is necessary, regardless of other factors, to split two replicas from each other. By moving one replica towards the outermost border, one may save one cut on the cutting-machine (see figure).
When two (or more) different kinds of replicas are lying in a stroke, one can move the two kinds from each other until they reach the stroke-border. In this case, we say we are spreading a stroke in the length direction. When only one kind of replica lies in the stroke, then we can move 1 replica towards the stroke border. We call this: spreading a shelf in the length direction.