Cortes has visual guide on how he created it starting with simple pixels to be used as sprites and then animated with 3D vectors.
The rules of the contest:
- Must have an xmas theme
- Submissions may be up to 1k (1024 bytes)
- Submissions must consist of only js
- Any and all externals are strictly forbidden
- Must work on current browsers versions (ch, o, fx and sa)
- The eval family is NOT allowed this time
- You get canvas object, its context and body object for "free"
- Your demo must work in the "html5" shim provided
- Your demo must be submitted before xmas!
For more information the history of these sorts of contests, see the Wikipedia entry for Demoscene.