Variable: bb-board

bb-board is a variable defined in blackbox.el.gz.

Value

nil

Documentation

Blackbox board.

Source Code

;; Defined in /usr/src/emacs/lisp/play/blackbox.el.gz
;;; blackbox.el --- blackbox game in Emacs Lisp  -*- lexical-binding: t -*-

;; Copyright (C) 1985-1987, 1992, 2001-2025 Free Software Foundation,
;; Inc.

;; Author: F. Thomas May <uw-nsr!uw-warp!tom@beaver.cs.washington.edu>
;; Adapted-By: ESR
;; Keywords: games

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; by F. Thomas May <uw-nsr!uw-warp!tom@beaver.cs.washington.edu>
;; doc comment by Root Boy Jim <rbj@dsys.icst.nbs.gov>, 27 Apr 89
;; interface improvements by ESR, Dec 5 1991.

;; The object of the game is to find four hidden balls by shooting rays
;; into the black box.  There are four possibilities: 1) the ray will
;; pass thru the box undisturbed, 2) it will hit a ball and be absorbed,
;; 3) it will be deflected and exit the box, or 4) be deflected immediately,
;; not even being allowed entry into the box.
;;
;; The strange part is the method of deflection.  It seems that rays will
;; not pass next to a ball, and change direction at right angles to avoid it.
;;
;;                           R   3
;;               1 - - - - - - - - 1
;;                 - - - - - - - -
;;                 - O - - - - - - 3
;;               2 - - - - O - O -
;;               4 - - - - - - - -
;;               5 - - - - - - - - 5
;;                 - - - - - - - - R
;;               H - - - - - - - O
;;                 2   H 4       H
;;
;; Rays which enter and exit are numbered.  You can see that rays 1 & 5 pass
;; thru the box undisturbed.  Ray 2 is deflected by the northwesternmost
;; ball.  Likewise rays 3 and 4. Rays which hit balls and are absorbed are
;; marked with H.  The bottom of the left and the right of the bottom hit
;; the southeastern ball directly.  Rays may also hit balls after being
;; reflected.  Consider the H on the bottom next to the 4.  It bounces off
;; the NW-ern most ball and hits the central ball.  A ray shot from above
;; the right side 5 would hit the SE-ern most ball.  The R beneath the 5
;; is because the ball is returned instantly.  It is not allowed into
;; the box if it would reflect immediately.  The R on the top is a more
;; leisurely return.  Both central balls would tend to deflect it east
;; or west, but it cannot go either way, so it just retreats.
;;
;; At the end of the game, if you've placed guesses for as many balls as
;; there are in the box, the true board position will be revealed.  Each
;; `x' is an incorrect guess of yours; `o' is the true location of a ball.

;;; Code:

(defvar bb-board nil
  "Blackbox board.")