Hi Cavac,

Can I just say I've really enjoyed thinking this one over. Thanks for posting. Now I have already come across this puzzle before and knew what the best option would be. However I have never until now really delved into the math and certainly never tried to apply such a problem into code. I may try and do so with other problems I come across, as an ongoing training technique.

At first I thought I was going to have to use arrays and hashes or a mixture of the two. However after thinking about it and trying to reduce the significance of the array/hash values, and coding, I came up with what I think is a fairly straight forward conditional routine that tests for both the punter sticking and changing after each initial guess.

I made an effort to approach the problem as if I had never seen it before and did not know the outcome already too. I hope that the module retains it's integrity for that

no data structures required I think. Happy Xmas & New Year!

Don