Days 3 and 4 were a little slower. There were some issues at work that were left in a slightly less than resolved state. So, I divided my time between working on work and Thumbscrew. I finished the internal Thumbnailer module, so it can act as a standalone. It will be communicating back with Thumbscrew via NSNotifications. Unlike Zope 2 or Zope 3 Events, NSNotifications are sent to a name rather than an Interface object, so I wrote another little app, called ListenUp! which takes an Event Name and listens for it, spitting out the contents of the NSNotification's object payload. Here's a screenshot, with Thumbnailer running in the background: