Each pipeline, valve, instrument, and other physical instrument or equipment in your factory or plant is represented in a Visio diagram by a component shape. Piping shapes lay out the direction of flow. Minor pipelines connect to major pipelines. Pipe endpoints connect to equipment shapes. Valves rotate into position on pipes, splitting a pipeline into two pipes, each of which is glued to the valve and tagged with the same number. Instruments also attach to the components they monitor. What holds everything together is glue. You know that shapes are glued when you drag one toward another and a red square appears around a selection handle or connection point, as shown in Figure 27-17. When shapes are glued, they move together. For example, you can drag a pipeline to reroute it, and valves glued to the pipe move with it.