blep.rkt

#lang racket

(define start '(0 3 3 3 0 1))

(define a '(3 2 1 1 0 0))
(define b '(0 0 1 0 1 0))
(define c '(-1 1 -2 1 -2 1))
(define d '(1 1 1 0 3 1))
(define e '(-2 +2 0 -2 +2 -2))

(define (0? l)
  (andmap (λ (x) (= x 0)) l))

(define (use state thing)
  (map (λ (a b) (modulo (+ a b) 4)) state thing))

(define (try-stuff state path as bs cs ds es)
  (cond [(0? state) (printf "~a~n" path)]
        [else (when (< 0 as)
                (try-stuff (use state a) (cons 'a path) (- as 1) bs cs ds es))
              (when (< 0 bs)
                (try-stuff (use state b) (cons 'b path) as (- bs 1) cs ds es))
              (when (< 0 cs)
                (try-stuff (use state c) (cons 'c path) as bs (- cs 1) ds es))
              (when (< 0 ds)
                (try-stuff (use state d) (cons 'd path) as bs cs (- ds 1) es))
              (when (< 0 es)
                (try-stuff (use state e) (cons 'e path) as bs cs ds (- es 1)))]))

(try-stuff start '() 3 3 3 3 1)