I believe this is all the code for it: https://gist.github.com/2476246. Line 343 (the $ function declaration) initialized the script and line 363 initialized the canvas element. You're right, not CSS3.
The two image sprites are http://www.google.com.au/logos/2012/sundback12-hp-l.jpg and http://www.google.com.au/logos/2012/sundback12-hp-s.png.