Once in a while someone mails us a puzzle. We received the "Zebra" puzzle in 1998, and solved it the same year. The "Eden" puzzle arrived in December 2002, and we solved it in February 2003. Frankly, we're not very good at these!

If you're a math or logic teacher, or regularly solve the teasers in the Scientific American, we'd like to see (and publish) a general approach to upgrade our destitute Puzzle thinking toolkit.

See what you can do with these. Challenge yourself!

For readers who write with solutions or a bona fide effort, we've posted password-protected solutions. Write us with what you have or believe you have, and we'll email you the URL, user name and password where you can see what we came up with!