While I like classes, the first 4[1] programming languages I used did not have classes. The first dialect of the first language I learned didn't even have functions!
1: Basic, Logo, C, Pascal. Logo and Basic I learned 2 fairly different dialects of even (Atari/Apple and GW/Quick respectively).
Eh, I think classes are closer to Eukaryotes having mitochondria than something as fundamental as cells. Cells seem to be a prerequisite for complex life while classes are definitely not a prerequisite for complex programs.
