b$.$ Buy stamps from a postal clerk.

I Clerk fills order or suggests alternative if out of requested stamps. III Clerk greets customer.

II Clerk gives customer the stamps and collects money. IV Clerks are paid.

$\backslash$table$[[$Customer actions,$\backslash$table$[[$Arrive and wait in$],[$line if necessary$]],,\backslash$table$[[$Customer approaches$],[$clerk$.]],\backslash$table$[[$Customer requests$],[$stamps$.]],\backslash$table$[[$Customer pays for$],[$stamps$.]],$Leave.$],[$line of information,$,x,,,,],[$Contact person$($s$),,$Clerk calls next in line.,,,,$],[$line of visibility,,,,,,$]]$

Backstage contacts

line of internal interaction

Support

Schedules are made.

Stamps are reordered

Cash and stamps are

as needed.

reconciled.