Bringing to fruition the tantalizing properties, foreseen since the discovery of carbon nanotubes, has been hindered by the challenge to produce a desired helical symmetry type, single chirality. Despite progress in postsynthesis separation or somewhat sporadic success in selective growth, obtaining one chiral type at will remains elusive. The kinetics analysis here shows how a local yet moving reaction zone (the gas feedstock or elevated temperature) can entice the tubes to follow, so that, remotely akin to proverbial Lamarck giraffes, only the fastest survive. Reversing the reaction to dissolution would further eliminate the too fast-reactive types so that a desired chirality is singled out in production.