“The line between entertaining math and serious math is a blurry one,” Martin Gardner wrote in the August 1998 issue of Scientific American. Gardner, who died in 2010, was this magazine's Mathematical Games columnist for a quarter of a century, until he retired in 1981. His fans have worked hard to maintain that blurriness, most recently in March at the 11th Gathering 4 Gardner, the biennial reunion dedicated to celebrating the polymath's contributions to mathematics and its relation to art, music, architecture and, well, fun.

Gardner loved recreational math, and his readers would take his observations and run with them, improving and generalizing to Gardner's delight. For example, he originally gave a solution in his column for the old challenge of arranging six cigarettes so that each one touches the others (right). His readers went on to find that seven cigarettes could also meet the requirements, and in 2013 mathematicians found that seven circular cylinders of infinite length could as well.

This year the meeting's attendants talked about at least 50 such problems, avoiding the cut-and-dried math education experience that is known to so many. Most of the 243 presentations were concerned with art or music: The beauty of stochastic geometry. Holographic visualizations. The relation of music to the Platonic solids. One presenter, cellist Philip Shepard, discoursed on string theory—the theory of stringed instruments in this case.

And magic made an appearance, of course. A well-known inventor of magic tricks, Gardner had shied away from performance. He did not, however, shy away from advocating awe, surprise and wonder in math—a talking point at the meeting—and wrote several essays on how a sense of wonder is the antidote to the hubris of the human condition. It is a testament to that enduring sense that so many people inspired by Gardner are compelled to seek one another out and puzzle over puzzles.