I've written 4 blog articles on the JavaFX sequence implementation that should be of interest to those who want to know how it works
and what it costs
. This covers the 1.2 Marina
implementation.
This is probably the best order to read them:
http://per.bothner.com/blog/2009/JavaFX-sequence-basics/
http://per.bothner.com/blog/2009/JavaFX-unboxed-sequences/
http://per.bothner.com/blog/2009/JavaFX-sequence-updating/
http://per.bothner.com/blog/2009/JavaFX-sequence-triggers/