+---------------+ | +-------+ | JACK ----->|-> A ->|---+ | | | +-->|-> B ->|----------> JACK +-------+
+-------+ | | +---|<- C <-|<--+ | | | | | +-------+ | | | | +-------+ | JACK ----->|-> A ->|---+ | | | +-->|-> B ->|----------> JACK +-------+
(also available as an attachment)
+---------------+ | +-------+ | JACK ----->|-> A ->|---+ | | | +-->|-> B ->|----------> JACK +-------+
+-------+ | | +---|<- C <-|<--+ | | | | | +-------+ | | | | +-------+ | JACK ----->|-> A ->|---+ | | | +-->|-> B ->|----------> JACK +-------+