Hello everyone! My name's Mark Johnson, and alongside Professor Simon Colton (http://ccg.doc.gold.ac.uk/simoncolton/) of the Computational Creativity Group (http://ccg.doc.gold.ac.uk/) at Goldsmiths College and an artificial intelligence known as the HR system (http://www.doc.ic.ac.uk/~sgc/hr/), we've been developing a new kind of paper puzzle game. We're calling it Donatsu!

The HR system is a piece of software that automatically creates mathematical concepts and discovers conjectures about them. The system is now capable of generating and testing the solvability of puzzles within wide constraints, and we’ve developed a set of puzzles we’re calling Donatsu (transliterated Japanese for “Doughnut”). These involve the player following a loop (or various other loop-like designs) attempting to get a series of numbers to reach particular totals through adding mathematical operators (+, -, /, and x). 

I've pasted in below four of the many permutations we've developed - Uninatsu (the most basic), Chromanatsu, Maxinatsu, and Hexanatsu (the most complex) - alongside appropriate instructions. You can also download to print off a paper version, since these are paper puzzles, after all! Our long-term goal is to develop and refine these to the point that we can potentially get some published in newspapers. 

Seeing as these are designed to be done with pen and paper, you can download a PDF of all the puzzles here: http://www.ultimaratioregum.co.uk/game/download/donatsu-v1/?wpdmdl=6391

So: we'd love to get your feedback! Aside from the obvious - are these fun and interesting to solve - we'd also like to ask two main questions: 1) which did you like most, and why, and 2) what would you improve about the puzzles? This is still the early stage of development, so we're trying to pin down the best puzzle permutations possible. Thanks!

The satisfying aha moment happened when I figured some strategies on how to solve the puzzles but that happened once instead of happening many times per puzzle. After solving a few, I was no longer driven to solve more. I only got part way through the first loop.

There may be some people who would love this kind of puzzle but I don't think I fit in that group.

For me, the downsides are there is a too much mental calculation and I feel like I am just brute forcing an answer. There doesn't seem to be a way you can partially solve a loop and come back to it later. It is all or nothing since each operation depends on every other operation in the loop. There also needs to be more interlinked answers like you have in chromanatsu and hexanatsu. Those are great because they let you solve one loop and that gives you information to help you solve another loop. That only works if there is only one solution to each loop though.

My main suggestion would be to shorten the loops when first introducing the concept. If you could get familiar with the concept using loops of 4 then work your way up to larger loops, then it would give players time to develop strategies to find answers while keeping them in flow.

In my view, that is WAY too much brainpower to be fun.

Consider the math functions that are popular in games and social media right now.  Two operations and people share it.  Three operations and people get confused.  Four operations and people start with arguments about operator precedence and end with deathmatch arguments about parentage and intelligence, with many people unable to figure out the basic mathematics.

These puzzles are 30+ operations. They are a mishmash of the four basic math operations in the hope of finding a combination of five operations that gives the desired results.  Unless your target audience is primarily academics studying mathematics I don't see any traction as "fun".

I don't think you could get them published in newspapers like Sudoku is unless they are radically simplified. Sudoku's rules are much easier since the puzzle requires 1-9 in each region. You can use additional math, but the low difficulty puzzles can be solved by repeatedly counting to nine. Most young children can solve them simply by counting to nine over and over and over again.  These puzzles, in contrast, requires keeping at least five math operations in your brain to solve.