Thursday, 4 October 2012

World Puzzle Championship 2012: Round 3 Twisted Puzzles

The third round of the WPC feature a number of classic puzzle type, with a slight twist. This slight twist usually means one of the main rules of the genre is broken and can't be applied while solving till you've fixed the twist. The twists in the puzzles not featured in this post are are an Easy as ABC clue in a Skyscraper puzzle, extra numbers in a Domino puzzle, empty cells in Kakuro and Arrows puzzles, 2 touching ships in a Battleships puzzle and an incorrect clue in a Four Winds puzzle.
I opted to design a Worms, Star Battle, Ariadne's Thread, Tents and Trees and Magnets variant. These were chosen for different reasons. Worms and Ariadne's thread I had never made myself and wanted to see how they are constructed and what the impact of the extra rule was. Star Battle I saw as the most dangerous twist to make a mistake in and construction clearly showed I was right as my first 2 attempts were broken as I had messed up with the twist somewhere. The Tents and Trees isn't so much different, but it was important to get one automatic solving technique out. the Magnets was just because I like designing Magnets and that was all for my own constructing pleasure.
I hope they are enjoyable, I surely enjoyed constructing them.

Puzzles can be found below.

3-1 Alien Worm

Fill the grid with 5 cell worms, built of the digits 1~5 in order. Equal numbers can't touch eachother, not even diagonally. Every white cell has to be part of a worm. Some digits are given. Additionally, there is a single alien worm in the grid of length 7, built up of the digits 1~7 in order.

3-3 Spy Star

Place 2 stars in ever row, column and blackbordered area. Stars can't touch eachother, not even diagonally. Additionally there is one row, column and blackbordered area that contain 3 stars.

3-6 Intricate Connection

Draw a line that starts in number 1 and through all numbers in order and ends in number 10. The line rune horizontally and vertically and goes through all cells. The line can't touch itself anywhere. Additionally there is a single cell in the grid where the line crosses itself.

3-8 Friendly Campers

Place a number of tents in the grid. Each tent is orthogonally connected to a tree. The tents don't touch eachother, not even diagonally. Numbers on the outside indicate how many tents are located in that row or column. Additionally, there is one tree that has 2 tents connected to it.

3-9 Discharged Magnets

The grid is divided into 1x2 rectangles. Some of these rectangles contain magnets. Each magnet is made of a + and - pole. Equal poles can't touch eachother by a side. Digits on the outside indicate how many + and - symbols are located in that row or column. Additionally, part of the grid is left undivided. Figure out the correct layout for this area.

Click to enlarge


  1. I do not see an Ariadne's thread,though you wrote you had selected that.
    Intricate connection is really nice.I thought i found an opening in the worms puzzle in the top-right,but nothing worked.
    I think friendly campers is not quite a twist.I am not sure how it can be constructed to add novelty to the solve.Your design
    places the twist in the very end,without any influence on the solve.But i think this is the only way of employing the twist.

    1. Intricate Connection is a Ariadne's Thread with a twist.

      All twists here took away one standard rule, which made solving the puzzle different than normal. In some puzzle types the impact was bigger than others. In the Tents variant you could easily get tricked up if you would automatically cross out squares that only touch a certain tree after already having placed a tree next to it.