Start with JIT first, then do proper multithreading. Guido haven't done the first, neither he
cared much about the second -- apparently, the speed didn't matter to him. For me, it's a sign
of a sane person, a person who understands his objectives. After all, no one is writing JIT
compilers for shell scripts. Actually, I think shell scripting is an outstanding example of
what scripted languages are good for; not that I like shell syntax, implicit vars etc -- but
the idea is just right.