Blackbox is a clever two-player deductive game invented
by Eric Solomon in
the 1970s. Your goal is to discover the whereabouts of five atoms
in a black box by sending rays of light into the box and observing
if and where the rays emerge. An atom will either absorb a ray
if the ray hits it head on, or deflect a ray through 90°
if it comes close (passes through an adjacent row or column).
Two deflections can occur at the same time forcing a ray to return
and emerge at its entry point, this is referred to as reflection.
The challenge is to pin point the location of all atoms using
the least number of rays. If you wish to commit your solution
and to discover your score you must have exactly five
guesses marked, then click on Reveal. The five hidden
atoms will appear marked as @.
Click New Game to generate another arrangement of hidden
Click Reveal to check you guesses and display the position
of the atoms.
To activate a ray click on one of the edge buttons marked
with a #.
To mark your guesses with a ? click on the unmarked
To undo a guess just click on it again.
Your score will be 36 (the total number of ray buttons) minus
the number of ray buttons used, minus 5 for each incorrect guess.
Any score in double figures is good!
What happens in the box?
The diagram below illustrates how rays sent into the box interact
with the atoms. Absorbed rays are labelled A. Reflected
rays are labelled R (note that the two types of reflection
(the brown and green rays) are indistinguishable). Rays which
propagate through the box from one point to another (as with
the red ray) have their entry and exit points marked with a unique
Deflected by atom a.
Absorbed by atom a (direct hit).
Absorbed by atom d rather than deflected by b (absorption
overrides deflection when two atoms sit side by side).
Reflected by atoms a and b (the ray is deflected
by both atoms in turn so that it's path turns back on itself
and emerges where it went in).
Reflected before entry by atom c (this is a special case
Note that rays may be deflected several times before emerging
from the box, or before being absorbed or reflected.
Eric Solomon (marketed by Waddingtons Games - 1976)
applet © Andrea Gilbert 1997