At the XML Summer School, my marra Marc Hadley and I ran a short workshop on designing REST Webby services. We used pin-boards around the room, along with index cards:

which we connected with ribbon to paper-prototype HTTP message flows:

People seemed to like the cards, adopting them as labels:

All was going well until someone slipped "204 - No Content" into my badge holder. This made me grumpy, because everybody knows I'm 418.

I had fun spray-mounting them onto card, and even without calendering, cutting round corners gave them a pretty nice playing card feel. I might turn them into fridge magnets. Maybe you'd like to, given they're under a Creative Commons License! Anyway, it's early days, and I'm still not exactly sure where this experiment is going. Jeremy Ruston wondered about tessellation, or even if they could be made to perform work, a bit like Napier's Bones? Watch this space.