There is a simulation program for KYTRONs. It is written in ClIM 2 and Common Lisp. It is available from the Macintosh Common Lisp and CLIM ftp-site on ftp.digitool.com:

ftp://ftp.digitool.com/pub/mcl/contrib/clim/clim-2/kytron2.lisp

(There exists an older version named KYTRON.lisp running on CLIM 1.1 too.)

Here is an MPEG movie showing a running CLIM-simulation.

The following is the main comment in the Lisp source file:

;;; Simulation of KYTRONs on the Moon.            *** CLIM 2 version ***

;;; ABSTRACT: 
;; KYTRONs are small autonomous vehicles which try to find a bright light source (e.g. the sun) 
;; to be able to recharge their batteries from their solar panels. 
;; They live on a moon-like surface with obstacles. The (randomly computed) landscape 
;; consists of craters and mountains which the KYTRONs cannot climb.

;; KYTRONs are real - they were built by rm from 1974 to 1980 (KYTRON 1, KYTRON 2, 
;; m-KYTRON 3, c-KYTRON 4, and KYTRON 5). c-KYTRON 4 has a MC14500B micro-controller and 
;; 256 words of program memory. The other KYTRONs are controlled by pure digital hardware 
;;  - no software, only SSI CMOS circuits.

;; This CLIM program is a toy simulation application written to be 
;; portable under CLIM 2 (currently developed in 
;; Lucid Common Lisp 4.1.1 and CLIM 2.0 beta) 
;; If you note problems with other platforms, please let me know - 
;; currently I do not have access to other platforms.

;;; GOAL: 
;; The primary goal was to learn the most important CLIM concepts: 
;;         - application-frame 
;;         - pane 
;;         - command 
;;         - presentation-translator 
;;         - drawing 
;;         - incremental redisplay 
;; Only the upper-layer functions of CLIM are used as far as it was possible. No low-level 
;; programming. The powerful CLIM default-mechanisms for presentation-types, 
;; presentation-translators, command-tables etc. are used extensively, which keeps the 
;; GUI-part rather short. See the comments for exceptions.

;;; HOW TO USE: 
;;  After compiling and loading the file, start the simulation application by evaluating 
;;  (common-lisp-user:open-kytron). 
;;  Then you may add some KYTRONs with "Add KYTRON ..." and modify the 
;;  landscape by adding new (randomly placed) elements or deleting some of the existing. If 
;;  some KYTRON is placed accidently on an obstacle, please move it to some free place using 
;;  "Move Object". 
;;  Then you start the simulation with "Run Simulation". Stop it anytime with a mouse-click 
;;  in the main pane. After quitting, you may resume with the last state 
;;  of the environment by evaluating (common-lisp-user:open-kytron). Use a "KYTRON 2" for 
;;  best results. It handles rather complex situations.

;;;====================================================================

;;; CONTENTS OF THIS FILE: 
;;; (1)----- basic classes -------------------------------------------- 
;;; (2)----- misc. ---------------------------------------------------- 
;;; (3)----- discrete simulation of an analogue Monoflop -------------- 
;;; (4)----- the MOON surface ----------------------------------------- 
;;; (5)----- basic KYTRON functionality ------------------------------- 
;;; (6)----- KYTRON simulation  --------------------------------------- 
;;; (7)----- light searching ------------------------------------------ 
;;; (8)----- geometry ------------------------------------------------- 
;;; ------------------------------------------------------------------- 
;;; (9)----- the CLIM GUI --------------------------------------------- 
;;;(10)----- presentation by drawing ---------------------------------- 
;;;(11)----- basic geometric drawing ---------------------------------- 
;;;(12)----- CLIM commands -------------------------------------------- 
;;;(13)----- hacks for obstacle detection ----------------------------- 
;;;(14)----- initialization -------------------------------------------

;;;====================================================================