Mar 11, 2011 at 5:43 PM

Although I have not yet attained elightenment, these Koans have been a big help.  Many thanks!

And a further request.  One of the great promises of reactive programming is a simplification of the complicated state logic one needs to maintain for GUI interactions.  Although there are simple examples of dragging an image around on a canvas available, a simple drawing app which shows how to activate/deactivate subscriptions, reuse of subscriptions for different drawing needs, and generally how to structure such an app in a reactive world would be beneficial.

Keeping it as simple as possible, what is the minimum code required to:

Draw a polyline.
Draw a rectangle.
Select an existing shape for editing.
Edit existing shapes by dragging vertices.

Having a definitive example of this would probably do much to spur interest in the reactive world.