step one: solve it in LISP step two: tell a C compiler how to do it (although the solution I would write first in LISP isn't actually what I would do in C; in

step one: solve it in LISP step two: tell a C compiler how to do it (although the solution I would write first in LISP isn't actually what I would do in C; in C, I'd start with stack/cons-like linked list and do a slinky-queue shift)