I recently released a tool built with Decker called WigglyPaint:

While WigglyPaint is capable of exporting drawings as GIF animations, Decker users should also be aware of a nifty secret feature: the main WigglyPaint drawing surface is a contraption!

By copying and pasting this contraption, you can add wiggly animated drawings to your own decks without writing any code:

Note that you may wish to lock the pasted contraption (as shown above), to prevent stray extra scribbles!

Populated "wiggler" contraptions take up roughly 4x as much space as a static drawing of the same size, so be sure to crop them appropriately before exporting. They will also respect the ".show" attribute, so semi-transparent wigglers are possible.

Thanks for posting this I was just trying to figure this out when you posted.

Its too good.

I love it. 

Honestly, this is making me want some sort of hyper OS on top of Decker. Some sort of Desktop/supervisor (I hesitate to say hypervisor) etc, where the programs are decks. Like, a Finder/desktop environment with folders where files can be stored etc. Decks can execute other decks. Mount deck images etc. Lil as a shell. Lil scripts as icons that can also be run with a double-click. I dunno, just spitballing ideas. Probably getting too sophisticated for a web app/authoring tool. 

I also would eventually like to see a "home stack" feature like the original HyperCard where we could take several stacks (like zine articles) and put them all together with a parent home stack. 

I think that it's neat that this little applet alone is attracting people to Decker.