Bulls and Cleods

Here's an idea for a fun, little no-expense, no-tech game that you can play with another, needing only paper and pen. It's a good game to play while stuck waiting in lines or in waiting rooms. When I learned it as a kid, it was called "bulls and cleods". [I'm not sure how to spell "cleods", having looked up the word in the dictionary and the Internet with no success.]

Each side in bulls and cleods imagines a four-digit string of non-repeating numbers (e.g. 2345, 6452). They then take turns submitting "guesses" to each other in order to finally determine the other's number. The first to do this wins the game.

The terms "bulls" and "cleods" come into play regarding the hints the "holder" of the number gives the "guesser" each time around. For example, suppose I have imagined the number "1234" and my worthy opponent guesses "2614". I see that "2614" contains three digits in my number of "1234". "4" is present in the exact correct position (a "bull") while "1" and "2" are also present, but in the wrong places ("cleods"). So my response to my opponent's guess of "2614" would be "one bull and two cleods". Using logical reasoning, eventually someone hits upon the exact number and wins.

This game can be played among most age groups. Naturally, little children may find it too challenging, but here it can be used as a teaching tool for logical reasoning.