### Random Post

### Recent Posts

- Puzzle 69: Division: letters for digits
- Enigma 1106: Not a square unused
- Enigma 405: Uncle bungles the answer
- Enigma 401: Uncle bungles the answer
- Puzzle 70: Football five teams: new method
- Enigma 1107: Factory work
- Enigma 404: Regular timepiece
- Tantalizer 477: Precognition
- Enigma 1108: Every vote counts
- Enigma 403: Taking stock

### Recent Comments

saracogluahmet on Enigma 1740: Sudoprime | |

Jim Randell on Enigma 1740: Sudoprime | |

geoffrounce on Enigma 1740: Sudoprime | |

geoffrounce on Enigma 1730: Prime positi… | |

Jim Randell on Enigma 389: Missing, presumed… |

### Archives

### Categories

- article (11)
- enigma (1,087)
- misc (2)
- project euler (2)
- puzzle (23)
- site news (42)
- tantalizer (23)
- teaser (3)

### Site Stats

- 159,091 hits

This Python program tries to fit the dominoes into the grid recursively, checking the products as rows and columns are completed. It runs in 3.2s.

Solution:The four horizontal dominoes are: 1-2, 2-2, 3-4 and 4-4.Here is a diagram of the layout of the dominoes (horizontal dominoes are shown in red, vertical dominoes in blue):

There are two other ways to lay out the dominoes which give the same numerical grid, but each of them has six horizontal dominoes: