"Black Box +" is the scientific term for some object with an unknown mode of operation, but which produces observable effects when stimulated in some way. By study of these effects it is sometimes possible to deduce the internal operation of the black box.

In the game "Black Box +" one player secretly places a number of 'atoms' in the cells of a grid to form a 'molecule'. The other player (the scientist) selects and marks positions at the edge of the board from which he shoots 'rays' into the box (the game board), and is told where they emerge, or if they do not emerge at all, that is, are 'absorbed'. Knowing how individual atoms affect a ray, he tries to deduce all the cells containing atoms. Of course, a ray might encounter more than one atom or, perhaps, none at all.