Thursday, 23 August 2012

Puzzle #125: Ripple Effect

Here's another Ripple Effect puzzle. It's been a while since I posted one. this is mostly caused by the fact that I've been writing Ripple Effect puzzles for Breinbrekers as well. It's not always easy to find good openings for clueless grids. It also helps to not make any errors. The construction took a while as I had made a mistake very early on and didn't notice after finishing the puzzle on my fifth try. Took me another four attempts to fix that mistake correctly. But in the end I think the puzzle worked out well. I have used a similar opening before. It's moderately hard, as most my Ripple Effect puzzles are.

Rules for Ripple Effect


  1. Thanks for another very nice puzzle.

    I started by noticing one particular digit has a special interaction with the central 6x6 area. And then it all flows from there.

    Also, I noticed an interesting phenomenon, that for almost all your Ripple Effect puzzles, that particular digit is always the first one to be cracked (i.e. having the most instances placed before other digits). Wonder is it by design or just my own solving style?

    1. It happens a lot that a single digit will be very quickly placed in my puzzles (usually 4 or 5). This is partly by design, but also a feature of this puzzle type. There is a limited number of each digit you can fit in a 10x10 grid. Max 20 4s, max 18 5s. So after you have made an opening, the locations of your 4s and 5s will usually not allow the maximum number of 4s or 5s to be placed anymore. But you still want to utilise many larger rooms, so there exists no new opening in your puzzle. So you try to maximise the amount of higher digits you can still put in your puzzle. Because this is maximised, you can preplace a lot of these 4's and 5's before you have drawn the room they will be in. And thus, when people will solve they can already place these preplaced numbers later on, as those spots will logically turn into the only place they can still fit into a room you have designed later. As you know this number of 4s is the maximum, you can be sure these preplaced digits will hold true, no matter how the rooms look.
      This is something you have to keep track of when designing these puzzles. You don't want to end up with a large area where you can't place any 4s or 5s and end up having to only use size 1, 2 and 3 cages. It can even happen that you can't fit enough 3s or 2s in the grid. The easy way to aviod this clumping phenomenon is by using a lot of smaller cages or giving givens, which are 2 things I'm not a fan of. I just love you can design a numbers puzzle, which doesn't have and (number) clues.

    2. Right, it makes perfect sense now that you've explained it. I can't agree with you more that a number puzzle without number clues is an puzzle of beauty and elegance. Another nice pattern would be having minimal number of clues but all cages being rectangular, though I guess it would be pretty hard to create.

  2. 39:26..start was very difficult ..I enjoyed solving it