docs: diagrams for callback, circuit breaker, client session, collecting parameter, colletion pipeline, combinator, command, commander, component, composite entity, composite view, composite, context object, converter, crtp, currying

command/README.md

@@ -34,6 +34,10 @@ Wikipedia says
 
 > In object-oriented programming, the command pattern is a behavioral design pattern in which an object is used to encapsulate all information needed to perform an action or trigger an event at a later time.
 
+Sequence diagram
+
+![Command sequence diagram](./etc/command-sequence-diagram.png)
+
 ## Programmatic Example of Command Pattern in Java
 
 In the Command pattern, objects are used to encapsulate all information needed to perform an action or trigger an event at a later time. This pattern is particularly useful for implementing undo functionality in applications.