M&M commercial

[Leprechaun]

Does anyone remember that M&M commercial with the waves? it looked like a sea of M&M's, and they changed color as they flowed? Does anyone know how they did the color changes? heres a link to what im talking about if noone else has seen the commercial.

http://us.mms.com/us/fungames/tv/play_mpg.jsp?movieid=River_of_Chocolate_low

[Bytehawk]

my guess : a picture sequence applied with world coordinates