That bring me a memory of building something very similar to this at work. So back in time I worked on an online game server framework and we needed some sort of technical demo, and it occurred to me that a multiplayer jigsaw puzzle would work. I quickly prototyped an JavaScript client and that eventually became a fully-blown online social game, but the project was shelved because we had other things to work on. A glimpse of that client can be seen in my website [1]. (The prototype was built in my spare time so I could release this in public. It was a mistake to build this on SVG, by the way.)