Lights Out

I have come to the borders of sleep,
The unfathomable deep
Forest where all must lose
Their way, however straight,
Or winding, soon or late;
They cannot choose.

Many a road and track
That, since the dawn's first crack,
Up to the forest brink,
Deceived the travellers,
Suddenly now blurs,
And in they sink.

Here love ends,
Despair, ambition ends,
All pleasure and all trouble,
Although most sweet or bitter,
Here ends in sleep that is sweeter
Than tasks most noble.

There is not any book
Or face of dearest look
That I would not turn from now
To go into the unknown
I must enter and leave alone
I know not how.

The tall forest towers;
Its cloudy foliage lowers
Ahead, shelf above shelf;
Its silence I hear and obey
That I may lose my way
And myself.

- November 1916

A simple puzzle game, of which an inexpensive handheld electronic version was made by Tiger Electronics.

The game is played on a 5x5 grid of lights, which can be "on" or "off". The game starts with a random arrangement of lights on. The object of the game is to turn all the lights out. How do you do this? Touching any light toggles its setting, and also toggles the setting of the lights one square up, down, left, and right from the selected light. (If the touched light is on a border or corner, only toggle those lights which are on the board. The board does not wrap around.)

It sounds very simple, but it can be very frustrating. Once you get down to one or two lights on, it's not so easy to put them out.

I would put a whole bunch of ASCII art fun here to illustrate the concept, but there's a web-based implementation at http://www.websitetoolbox.net/lightsout.html. Enjoy!