This was a game that I played on a computer at the Science Museum in London, when I was about 10. I was inspired by this game, and it was one of the many things that teased me into a career in computing.
Here is a version that I started to develop for others to try.
Note that I have developed this in steps, and committed the code to github at each step, so you can see how my thinking has evolved right from the initial design, through to the implementation that is here today.
You might find when using this with school children that some of the earlier versions are more appropriate.
Follow the history here, where you can see my thinking evolve gradually:
https://github.com/whaleygeek/guessinggame/commits/master
David Whale @whaleygeek