There are two ways to tell if the timing belt has been replaced. One is obvious-you are looking at a service receipt showing the replacement.
Swimlane diagrams are used whenever you need to show activities, tasks, or process steps which are being performed by different actors/roles. You can use swimlanes to group activities in an activity diagram or process flow by any category what you need: by role, by system, by department, etc.
The line of intersection of a layer with the horizontal plane is the strike. Paravanes are steel floats with torpedo-shaped bodies and a horizontal plane near the forward end. All six spines are equidistant, of equal size and similar form, and lie with their branches nearly in one horizontal plane.