Colm Mulcahy

Colm Mulcahy, Chair
Professor Emeritus of Mathematics at Spelman College, Atlanta 

Colm Mulcahy recently took early retirement from Spelman College, in Atlanta, where he had taught mathematics since 1988. He has written for, Huffington Post, Aperiodical, Scientific American,, and the Guardian. Colm first read Martin Gardner as a teenager, in Ireland, then got swept up in the waves of axioms and deltas and epsilons. A quarter century later he rediscovered Martin’s extraordinary output, and had the distinct pleasure of getting to know the man himself starting in 2000.

In his final article for Scientific American, in 1998, Martin had written: “For 40 years I have done my best to convince educators that recreational math should be incorporated into the standard curriculum. It should be regularly introduced as a way to interest young students in the wonders of mathematics. So far, though, movement in this direction has been glacial.”  Colm is a firm believer in the Gathering 4 Gardner Foundation’s commitment to stimulate curiosity and the playful exchange of ideas and critical thinking in recreational math as well as in magic, science, literature, and puzzles. He is determined to extend Gardner’s legacy and bring it to new and more diverse audiences.

Vickie Kearn, President
Former Mathematics Editor, Princeton University Press

Prior to retiring in April 2019, Vickie was the executive editor for mathematics and computer science at Princeton University Press for 18 years. Vickie always loved numbers and puzzles as a young child but it was her high school math teacher who really lit a spark by showing her the connections between the people and the equations. Every number has a story and a person behind it. She taught school for 8 years before beginning her 42 year career in publishing. Her goal has always been to connect every bit of math to the person responsible for it or to a use for it. No one should fear math and just as no one hates music, no one should hate math. Her goal as a member of the board is to continue to promote the joy Martin Gardner brought to recreational math.

Robert Vallin, Secretary
Mathematics Professor, Lamar University

Robert W. Vallin is a mathematics professor at Lamar University in southeast Texas. He’s the author of research, pedagogy, and expository papers on several different subjects and of the book The Elements of Cantor Sets. He is the founder of the Special Interest Group of the Mathematical Association of America for Recreational Mathematics (SIGMAA-Rec). Outside of mathematics he is a magic enthusiast with a predisposition toward card magic.

Rick Sommer

Rick Sommer, Treasurer
Executive Director, Stanford Pre-Collegiate Studies at Stanford University

Rick has a Ph.D. in mathematics from UC Berkeley. As assistant professor at Stanford he helped launch the Stanford University Mathematics Camp (SUMaC) in 1995, and around the same time he became involved in Stanford’s Education Program for Gifted Youth (EPGY). Rick has enthusiastically pursued these interests ever since, and now serves as Executive Director for Stanford Pre-Collegiate Studies.

Nancy Blachman

Nancy Blachman, Board Member
Founder, Julia Robinson Mathematics Festival

Nancy Blachman’s love of mathematics and puzzles goes back to her high school days when she took George Polya’s short course in mathematical logic, did a research project on continued fractions, and participated in the Saint Mary’s Math Contest, which was held at Saint Mary’s College in Moraga, California. These experiences taught her that it was more fun to learn by discovery than to be told how to solve problems or just apply formulae. She subsequently earned degrees in mathematics, computer science, and operations research from the University of Birmingham (UK), Stanford, and UC Berkeley, respectively. She has written several books on Mathematica, in 2003 created Google Guide, and in 2007 founded the Julia Robinson Mathematics Festival, which inspires students to explore the richness and beauty of mathematics in a cooperative environment.

James Gardner

James Gardner, Board Member
Professor Emeritus at the University of Oklahoma

Jim is a Professor Emeritus of Special Education at the University of Oklahoma, with interests in universal design for learning and assistive technologies. He manages the intellectual property of Martin Gardner, and is currently involved in a variety of projects with publishers and organizations to continue the legacy of his father’s work.

Bob Hearn Bio Photo

Bob Hearn, Board Member
Software Entrepreneur

Bob Hearn was raised on Martin Gardner books and Scientific American articles. This developed into a lifelong interest in mathematics and puzzles, leading to a Ph.D. at MIT and a resulting book, Games, Puzzles, and Computation, with Erik Demaine. Along the way he co-wrote the once-popular Mac program ClarisWorks, and participated in a number of other software startups. Bob’s other passion is running ultramarathons; he holds several age-group American Records. Bob has attended the Gathering 4 Gardner since 2002, and has been the G4G Program Chair and MC since 2015.

Doris Schattschneider, Board Member
Professor Emerita of Mathematics at Moravian University

Doris Schattschneider holds a Ph. D. in mathematics from Yale University and is Professor Emerita of Mathematics at Moravian University in Bethlehem, Pennsylvania, where she taught for 34 years.  She is known for her work in discrete geometry and tilings. She has written and lectured extensively about the work of the Dutch artist M.C. Escher, and also the amateur mathematician Marjorie Rice,serving as her “Boswell.”  She is author of the book M.C. Escher: Visions of Symmetry and article “The Mathematical Side of M.C. Escher” (Notices of the American Mathematical Society) that document how Escher used mathematics, represented abstract mathematical ideas, and performed mathematical investigations. Currently an associate editor of the Journal of Mathematics and the Arts, she also serves on the advisory committee of the National Museum of Mathematics in Manhattan, NY.  She is a Fellow of the American Mathematical Society and  has been active in the Mathematics Association of America (MAA) at all levels, serving as editor of Mathematics Magazine 1981–1985.  In 1993 she received the national MAA Award for Distinguished Teaching of College or University Mathematics. 

Scott Vorthmann, Board Member
Software Architect and vZome Author

Scott Vorthmann earned a Ph.D. in Computer Science from Georgia Tech, with a minor in Mathematics. After some postdoctoral work at Carnegie Mellon University, and a brief and unsuccessful flirtation with entrepreneurship, he entered the enterprise software industry, where he has remained. Scott’s passion for recreational mathematics, born of many hours with Martin Gardner’s column in Scientific American, finds its principal outlet in the ongoing development of vZome (, a free software application for modeling Zometool ( and similar geometric systems. He also helps to coordinate meetings of “BAAM!”, the Bay Area Artists and Mathematicians, and enjoys hosting occasional meetings at his home.

Colin Wright, Board Member
Founder & Director, Solipsys Ltd.

Colin spends his time giving workshops and presentations exploring the surprising ways that maths pops up in unexpected places. He typically gives 150 to 200 presentations a year, 20 to 30 of which have been overseas, and is founder and director of Solipsys Ltd, a company that provides outreach and enhancement in STEM subjects, concentrating on mathematics. He is also a director of a company that does the maritime equivalent of Air Traffic Control, though his role there is now largely non-exec.
In his “free time” he juggles, and goes ballroom dancing. He plays piano (badly), Bridge (worse), and Go (worst of all). When necessary he will program in C, Python, fexl, and bash. He completed his PhD in Pure Maths at Cambridge University in the second half of the 80s, after completing his B.Sc.(Hons), also in maths, at Monash University, Melbourne, Australia.

Carolyn Yackel, Board Member
Mathematics Professor, Mercer University

Carolyn Yackel is a Professor of Mathematics at Mercer University. She is a leader in the field of mathematical fiber arts—and one of its initial promoters. For two decades she has co-organized an annual open gathering of mathematical fiber artists and she has co-edited three beautiful, multi-authored books that bring the mathematical fiber arts to life. An accomplished fiber artist who explores deep relationships between mathematics and art, she is currently expanding her craft to include other media. Dr. Yackel is also nationally active in undergraduate education, having chaired the Mathematical Association of America’s Committee for the Teaching of Undergraduate Mathematics.

Chair Emeriti

Tom Rogers

Elwyn Berlekamp

Bruce Oberg

Nancy Blachman

Advisory Council


Nick Baxter

Growing up solving puzzles and exploring the recreational side of mathematics, Nick was inspired largely by the many books from Martin Gardner. Nick regularly attends the annual International Puzzle Party, and serves as the USA president of the International Puzzle Collectors Association. He is also director of the annual US Puzzle Championship, and has led Team USA as a contestant or captain to 14 titles over the 28-year history of the World Puzzle Championship. He recently qualified for the Red Bull Escape Room World Championship. Nick lives in SF Bay Area, enjoying the active community of local puzzlers, mathematicians, and escape rooms. He has been fortunate enough to attended all 13 Gathering for Gardner conferences.


Mark Burstein

An erstwhile software engineer and now book editor by profession, Mark Burstein, a noted scholar, collector, and president emeritus of the Lewis Carroll Society of North America, has edited, introduced, or contributed to twenty books on Lewis Carroll, including editing and art-directing the 150th Anniversary Edition of Gardner’s Annotated Alice and the trade edition of Alice’s Adventures in Wonderland illustrated by Salvador Dalí. He also produced A Bouquet for the Gardener: Martin Gardner Remembered, which consists of a biography, remembrances, tributes, a bibliography, and a Festschrift by such writers as Doug Hofstadter, David Singmaster, Scott Kim, and Ray Smullyan.


Cassondra Darling

Cassondra Darling harbors a deep passion for old books, all things mathematical, and experiencing adventure. She learned from Martin Gardner that “you can’t find [adventure] by seeking it,” but rather “by taking advantage of accidents and coincidences,” and by “being aware constantly of the dramatic possibilities that are inherent in the ordinary.” Cassondra’s ordinary adventures have provided phenomenal opportunities to share her love of mathematics through teaching, to exploring the past by working in the History of Science Collections at the University of Oklahoma Libraries, and continuing to learn new ways to make knowledge more accessible to people through her current position as Discovery Librarian at OU Libraries. Cassondra’s yellow brick road recently led her to meeting the research archive of her “wizard,” Martin Gardner. She is currently working on creating a digital version of that archive.


George Hart

George Hart is a sculptor and applied mathematician who demonstrates how mathematics is cool and creative in ways you might not have expected. Whether he is slicing a bagel into two linked halves or leading hundreds of participants in an intricate geometric sculpture barn raising, he always finds original ways to share the beauty of mathematical thinking. Hart co-founded the Museum of Mathematics in New York City and developed its initial set of hands-on exhibits. He also makes videos that show the fun and creative sides of mathematics.


Evans Harrell

Evans Harrell is an emeritus professor of mathematics and former Associate Dean for Research at Georgia Tech.  He has taught math at all levels and in many parts of the world.  He was an early awardee of Tech’s Eichholz teaching award for his innovations in the calculus classroom, and he is known for research on quantum mechanics and geometric analysis.  Harrell headed up Tech’s effort to launch the Atlanta Science Festival in 2014, in partnership with Emory University and the Atlanta Chamber of Commerce, and has subsequently  produced several shows in the Atlanta area using circus arts, dance, music, and drama to communicate math and science to the general public.  In 2018 Harrell co-founded an educational nonprofit called Mathematics in Motion, Inc., to support works on mathematical themes by local performing artists. Mathematics in Motion has allied with the Atlanta Science Festival, Science in Vivo, The Georgia Tech Symphony Orchestra, the Julia Robinson Mathematics Festival, and the Celebration of Mind to showcase their products.


Scott Kim

Scott is a puzzle designer, visual artist and educational game designer. His puzzles have appeared in magazines (Discover, Scientific American, Games), electronic games (Tetris, Bejeweled), and books (The Playful Brain, with Richard Restak). He is the author of Inversions, a collection of his ambigram lettering designs. He has degrees in music and computer science from Stanford University. He is passionate about bringing games into math education, having designed educational games for ThinkFun and

Philipp Legner

Philipp Legner

Philipp is the founder of, an award-winning platform for learning mathematics, that makes online learning more interactive and engaging than ever before. In 2021, Mathigon was acquired by Amplify, one of the leading curriculum publishers in the US. Philipp studied mathematics at Cambridge University, mathematics education at UCL, and previously worked as software engineer at Google, Bloomberg and Wolfram Research.


Mark Mitton

Mark performs and produces events all over the world. He has performed magic for business leaders, star athletes, Nobel prize-winning scientists, royalty and rock stars, economic migrants on the island of Lesbos and hospitalized children around New York City. Inspired by Martin Gardner, Mark believes that the craft of magic can be used to consider surprising possibilities in many aspects of life, including mathematics, education, perception and memory.


Dana Richards

Dana Richards is a professor of Computer Science at George Mason University. His day job revolves around Theoretical Computer Science and Algorithms. His avocation revolves around puzzles and truthfully there is not much difference between the two. He has concentrated on the life and work of Martin Gardner. With just a little prodding he can be transformed into a Sherlockian.

Dave Richeson Advisory

Dave Richeson

David Richeson is a professor of mathematics and the John J. & Ann Curley Chair in Liberal Arts at Dickinson College. He received a BA in mathematics from Hamilton College and a PhD in mathematics from Northwestern University. He is interested in dynamical systems, topology, geometry, the history of mathematics, recreational mathematics, mathematics and the arts, and expository mathematical writing. He is the author of two books, Tales of Impossibility: 2000-Year Quest to Solve the Mathematical Problems of Antiquity (Princeton University Press, 2019) and Euler’s Gem: The Polyhedron Formula and the Birth of Topology (Princeton University Press, 2008). He was the editor of Math Horizons, the undergraduate magazine of the Mathematical Association of America, from 2014 through 2019, and he currently writes for Quanta magazine. He is grateful to his father for introducing him to the writing of Martin Gardner and to recreational mathematics when he was a child.


Érika Roldán

Érika Roldan’s mathematical research includes gamification and visualization technology. For almost twenty years, she has been implementing and developing outreach and educational projects in México, the USA and in several European countries with the main purpose of promoting the enjoyment and appreciation of mathematics and its application by the general public as well as increasing the enrollment of underrepresented minorities in STEAM. Erika founded BAMM at Ohio State University and co-founded Matemorfosis, and Music-Math. She is currently leading the research group Stochastic Topology and its applications at the Max Planck Institute MiS and is also affiliated with the Center for Scalable Data Analytics and Artificial Intelligence at Universität Leipzig, where she leads research projects on Computational Complexity, Educational technology, and Learning Analytics.


Mark Setteducati


Mark is a co-founder and past President of the Gathering for Gardner. He is a Magician and inventor of games, puzzles and magic, with over 50 of his creations marketed by companies worldwide. He is the author of “The Magic Show”, an interactive book that performs magic. In 2014, the Academy of Magical Arts awarded him a Creative Fellowship and lifetime membership to the Magic Castle, Hollywood, California.