An AKARI puzzle consists of a square grid in which some of the cells are painted black in the same way as in a crossword puzzle. Think of it as the
floor plan of a building in which the black cells represent pillars or wall segments. The remainder of the cells represent floor area which must be illuminated
by lamps placed in certain of the cells. A lamp illuminates all cells in its row and column up to the edge of the puzzle, or up to an intervening black cell. No
lamp is allowed to illuminate any other lamp, and the numbers in some of the black cells indicate the number of lamps which are adjacent to that cell both
horizontally and vertically. Each puzzle has a unique solution which does not require any guesswork to achieve. Puzzles can be built either manually or
automatically in sizes up to 16x16.
Solving an AKARI puzzle is a mouse only operation. A single click in any DARK cell will convert that cell to a NOLAMP cell which has a default
color of yellow. A second click will convert it to a LAMP cell, and all cells in its row and column will be converted to the LIT condition which has a default color
of white. One more click will convert it back to a DARK cell, and appropriate LIT cells will also be converted back to the DARK condition.