This is the classic board game Black Box, originally invented by Eric Solomon. This web page presents the standard version. You can also play the large version.
The yellowish area is the "black box". Four of the squares contain atoms which are hidden from the player. The player may click on the white squares around the border to fire rays into the black box. The rays will either be absorbed if they hit an atom directly, be reflected back out the same location, or be deflected by one or more atoms and exit the black box at a different edge location. In the latter case, a unique integer will be shown at the two corresponding edge locations.
The player may click on the yellow squares to place or remove "guesses" as to where he or she thinks that an atom may be present. These guesses are shown as blue circles. No more than four guesses may be on the board at any time.
The player may end the game at any time by clicking the "Try guesses" button, whereupon the actual atom locations will be revealed, and the final score displayed. Lower scores are better. Green circles represent atom locations correctly guessed; red circles represent atom locations which were not guessed, and blue circles with red crosses represent player guesses that do not correspond to an actual atom location.
Each ray fired into the black box adds one point to the score if it is absorbed (hit) or reflected, or two points if it exits the black box in another location. Five points are added to the score for each atom that the player failed to locate.
For details of how the rays are absorbed, reflected, or deflected by atoms, please see the Black Box entry in Wikipedia.
The applet and source code are available for download under the terms of the Free Software Foundation's General Public License, Version 2.
Last updated September 8, 2006
Copyright 2006 Eric Smith