### Random Post

### Recent Posts

- Enigma 426: Time and again
- Enigma 1084: 1-2-3 triangles
- Tantalizer 466: Diplomacy
- Tantalizer 467: Nine men went to mow
- Enigma 1085: Cut and run
- Enigma 425: Them thar’ Hills
- Puzzle 60: Uncle Bungle gets the last line wrong
- Enigma 1086: Stacking trays
- Enigma 424: A round of fractions
- Tantalizer 468: Shell fire

### Recent Comments

Brian Gladman on Enigma 426: Time and agai… | |

Jim Randell on Enigma 426: Time and agai… | |

Jim Randell on Enigma 1084: 1-2-3 triang… | |

Brian Gladman on Enigma 1084: 1-2-3 triang… | |

Jim Randell on Enigma 1084: 1-2-3 triang… |

### Archives

### Categories

- article (11)
- enigma (1,129)
- misc (2)
- project euler (2)
- puzzle (32)
- site news (43)
- tantalizer (34)
- teaser (3)

### Site Stats

- 169,972 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: