Martin Gardner passed away yesterday (May 22) at the age of 95 — a number that is 0 mod 1, 1 mod 2, 2 mod 3, and 3 mod 4, as I’m sure he’d appreciate. It seems like half the puzzles I hear about were either invented by him or popularized by him. Falling into the latter category are the flexagons, which are, of course, a favorite of Godzilla and which were described in the first “Mathematical Games” column of *Scientific American* (you know, according to Wikipedia).

A quick search reveals lots of puzzles, most of which have a visual component. As a treat, here’s a quick one that doesn’t (from the group Gathering for Gardner):

- Write out the alphabet starting at J (and ending at I):

JKLMNOPQRSTUVWXYZABCDEFGHINow erase all the letters that have vertical symmetry, like M.

There will be 5 groups of consecutive letters left. Write the number of letters in each group:

___ ___ ___ ___ ___

Cool, huh?

*Scientific American* itself just posted 3 Gardner puzzles here in tribute to the man who served them well for many years.

Martin, thanks for the fun.

*The photo of Martin Gardner was taken by Konrad Jacobs of Erlangen and is licensed under CC. From Wikipedia. *