Firelight Puzzle
How to Start:
There is a set of braziers in which a fire can be lit. When you click on or touch a lighted brazier,
it is extinguished and others around it lit. The aim of the puzzle is to light all the braziers
except the centre one out. If all the braziers go out, as can easily happen, you have failed dismally!
To start the puzzle again, tap or click on Start again and for some help tap Hint and it
appears at the bottom of the page. Your aim is to find the shortest solution which is just 11 moves.
And if you really give up, Solution gives the answer away appearing below the Hint.
History:
This puzzle goes back to one of the very first widely-available hand-held electronic games which
was introduced in 1978. It was called
Merlin
and was manufactured by the Parker Brothers game company. The
six puzzles
on the machine were devised by Bob Doyle and his wife Holly and this Magic Square was one. It started with a
random position and you could press ANY button, not just buttons that were lit. This simplifies the puzzle a lot
and brings it into the usual ‘Lights Out’ style of puzzle.
In 1979 the puzzle was included in a demo program for a speech recognition board that plugged in to an Apple
II computer. The developer added his own twist choosing to always start from the center-cell-on pattern, and with the
crucial restriction of only allowing players to choose cells already “on” in the on pattern.
Back to the front page
Or, now you are warmed up,
why not take a Polar Journey ?
Hint:
You need to work out how each brazier affects the others. Because this is such as small puzzle
there are only three different positions for a brazier - corner, centre of a side and middle, but there are actually 512
(2 to the power 9) different configurations of braziers lit and out to work with. This diagram shows which positions
are switched on or off when you click on the position shown in red.