anchor.diff:  
   
   (defclass voice-out-port (out-port)
  +  nil)
  +
  +
  +(defclass thought-in-port (stream-in-port)
  +  nil)
  +
  +
  +(defclass thought-out-port (stream-out-port)
     nil)
   
   
  
positive.code: (in-package :csp-sim)
  
  
  (defclass vibration-in-port (in-port)
    nil)
  
  
negative.code: ;; OVERVIEW
  ;;
  ;; CSP-SIM simulates a simple scenario in which two cans are connected
  ;; by a string (let's call it wire from now). A person talks into a
  ;; can and the wire will transmit the sound to the other can, where
  ;; the second person will hear it.
  ;;
  ;; Components:
  ;;
  ;;     thought-in-port  --> +--------+ --> voice-out-port
  ;;                          | PERSON |
  ;;     thought-out-port <-- +--------+ <-- voice-in-port
  ;;
  ;;
  ;;     voice-in-port  --> +-----+ --> vibration-out-port
  ;;                        | CAN |
  