Carmack seems to go through his FP phase. A phase that many programmers go through in their younger years (Carmack must have missed it, because he was occupied

Carmack seems to go through his FP phase. A phase that many programmers go through in their younger years (Carmack must have missed it, because he was occupied with Keen, Wolfenstein, Doom and Quake at that time), when they read SICP, learn Scheme, ML, etc. before the novelty wears off and they come back to plain old imperative, mutable programming.