Gadget models

Chris Double writes about using models to implement a clock. I've been working on a simple dataflow system based around "models" and "connections" for Factor's UI. When the design settles down, I'll document it, but basically you have your typical observable value cells -- these are "models" -- together with wrapper models which combine the values of other modules or change them in some way. When one model updates the change can propagate and affect other models which can eventually change what some gadget is showing.