With a company name such as "Enigma Scientific Publishing" it is appropriate that I have a section on brainteasers, to put the puzzle into Enigma. Every month from March 2016, I shall be publishing a new puzzle. The puzzles are mathematical in nature, but don't require much maths other than about high school leaving level, perhaps as high as A-level (UK). Some will be a bit more challenging than others, but they're mostly about logic. So if you enjoy Sudoku puzzles, especially the more demanding "killer sudoku" then you will probably enjoy these puzzles as well.
Competition:For each puzzle I have a competition. Please send solutions by email at email@example.com. Place the puzzle number in the subject address of the message. Correct entries will be given a number and the winning solution will be drawn at random. The prize will be a copy of one of e-books, but the main satisfaction will be knowing that you have got the correct answer. Entries close one month after competition opening.
Puzzle No. 1
The Christmas Tree Light March 2016 : Solutions by 1 April 2016
A Christmas tree light consists of 144 light emitting diodes (LEDs) arranged in a cubic lattice. Power is connected from one vertex of the cube to the opposite vertex. Each of the LEDs can be independently switched on or off, and the shortest paths are lit up consecutively. Each path is lit for 15 seconds before the next path is lit until all possible combinations of the cycle have occurred.
How long does it take for a full cycle to be completed?