David H. Arnold lived life passionately. Whatever David loved, he loved with his whole body and soul. He loved, for example, the Argentinian tennis star, Guillermo Vilas. In the mid-seventies, when Vilas was ranked number-2 in the world, David bought a New Hampshire vanity plate for his car: the plate read VILAS. And when David and his wife, Andra, bought a home in Stratham, David painted VILAS on his mailbox. The home was lovely, but his closest friends have always suspected David and Andra bought it, not so much for the house, but for what sat out in the backyard: a tennis court, but not just any tennis court. No, this was a clay court, and–you guessed it–clay was Vilas’ favorite surface.

Perhaps, what David loved most about Vilas was his exuberance and passion for the game. Lew Hitzrot, long-time friend and tennis partner, remembers the joy of David’s shouting, “‘Vilas,’ whenever he belted a backhand, topspin winner a la Vilas.”

To know David was to know that passion and unwavering commitment to task were the hallmarks of his brilliant career. He was a great teacher, coach, dormitory advisor, administrator, mentor, and friend. And he carried himself with a modesty that underscored the integrity we treasure in those who educate our children.

In contemplating his devotion to teaching, David once wrote, “From early on I seem to have had teaching corpuscles in my blood. I knew I would end up being a teacher. And . . . I dearly love doing exactly what I do.”

David may well have had teaching corpuscles in his blood. Born on February 21, 1941, the son of two secondary school teachers, David spent grades nine through twelve in a Connecticut boarding school. No doubt, the Loomis community influenced his life-long values, identity, and aspirations. After graduating from Loomis in 1959, David earned an undergraduate degree in mathematics from Middlebury College, spent three years teaching at the Hun School, and completed a master’s degree at Rutgers University in 1967. That same year, David accepted an appointment as an Instructor of Mathematics at Exeter. A two-year leave of absence from 1976 to 1978 enabled David to undertake Ph.D. studies in the History of Mathematics at the University of Toronto. We should note that he completed his dissertation only after returning to full-time teaching at Exeter. Nearly every morning, he did his writing between 4:00 a.m. and 6:00 a.m., sometimes taking a break by joining Eric Bergofsky on three-mile runs.

While Toronto loomed important in his post-graduate education, it paled in comparison to a moment far more important: it was in Toronto that David met Andra Crawford, the love of his life. When David returned to Exeter, he returned a married man.

In the fall of 1978, Ph.D. nearly in hand, newly married, and already having served as a faculty member for eleven years, David spent the next two-and-a-half decades living the life of an Exeter teacher and administrator. The list of his responsibilities underscores his sense of duty and a remarkable commitment to the Academy community. He taught math, chaired the Department, and spent three years as Director of Studies. He coached varsity football, j.v. football, baseball, soccer, and, of course, tennis. He served as a dorm head or advisor in Soule Hall, Kirtland House, and Dow House. He worked on numerous committees, including the Curriculum Review Committee which initiated significant changes in our academic offerings and school calendar. He spent a year abroad overseeing SYA in Rennes. From 1996 to 2001, he served as Clerk to the Board of Trustees. And, for many summers, he taught in EMI, the Exeter Mathematics Institute, a wonderful outreach program in which Exeter instructors facilitate math workshops for colleagues in schools across the country.

In all his undertakings, David held high the bar of excellence. His work did not go unnoticed. In 1986, he received a Brown Teaching Award and later became a recipient of the Rupert Radford ’56 Faculty Fellowship. In awarding David the Radford Fellowship, Principal Kendra O’Donnell noted David’s leadership, citing his steady hand in “guiding a talented and opinionated crew through the beginnings of major curriculum reform.” On David’s retirement in June 2006, Principal Ty Tingley extolled David’s gift for making the study of mathematics both invigorating and fun. Ty quoted a note David had received from Ursula Brewster, Class of ’90: “I wanted to write a brief note to you, thanking you for all you have done. I am one of the lucky few . . . to have you as a math teacher for an entire year. The love of mathematics you instilled into me as a Lower lasted all the way through my Exeter career and continues through my years at Yale. Thank you so much.”

David found myriad ways to make the classroom stimulating. One day, when his class was struggling to remember the quadratic formula, David threw open the window and yelled, “Does anyone know the quadratic formula? We need it up here to solve a problem.” Walking across the academic quad, science teacher, Jim DeCarlo, laughed so hard, he could not reply, though, of course, he “knew the question was not for him.”

David’s kindness and gentle sense of humor earned him great affection. Joyce Kemp recalls a moment when students made their feelings clear: “Picture a banner hanging from J. Smith . . . not advertising a weekend dance, but imploring in large letters: ‘Mr. Arnold, PLEASE teach 520.”

Given the opportunity to share memories of Mr. Arnold, Exonians from across the globe wrote to us. Collectively, their memories create a portrait of a brilliant, caring teacher, who encouraged students and strengthened their confidence in themselves. Neil Gesundheit, Class of ’70, felt “privileged to be in his Math 4 Calculus class. Mr. Arnold’s eyes would light up with excitement as he explained . . . the mystery and magic of calculus.”  Chieh-Min Fan, Class of ’81, remembers David’s “great good humor” facilitating an environment of lively discussion. Heath Marcus , Class of ’91, particularly appreciated David’s gentle prodding: David would sometimes draw a golden shovel “next to a student’s work when it was clear that they were just trying to BS their way through a solution.” Sue Safford, Class of ’83, notes the golden shovel was often accompanied by VE (valiant effort). Mr. Arnold “eased the sting of error with humor. He understood the delicate art of correcting without shaming to guide students to their own correct understanding of a concept.”

In every aspect of his work, David embraced a philosophy of in loco parentis: At Exeter, we have “boys and girls who need and deserve our presence and our guidance in and outside the classroom . . . I place a very high premium on my dormitory experience.” Lisa Weil, Class of ’78, cherishes living in Dow House where “home-made carrot cake and apple cider, served at a dorm meeting” encouraged “conversations between old and new students.”

Richard Maurer, Class of ’69, remembers the young Mr. Arnold as “a breath of fresh air. He was kind, understanding, and easygoing, without being permissive.” The day before he was to take the SAT, Richard broke his ankle and found himself in the Infirmary. He assumed “there would be no test for me. But the next morning, Dave . . . had a car pick me up and transport me to Phillips Hall, where I sat down as the test was getting underway. It was one of those Exeter ‘sink or swim’ moments that have prepared me so well for life.”

Doug Shenson, Class of ’73, arrived at Exeter in 1970. English by birth, Doug had never lived in the United States. More than fifty years later, he cherishes the warm welcome that put him “immediately at ease. Later, when I struggled to adjust to an unfamiliar math curriculum,” David “was extremely supportive and encouraging.”

If David was born to teaching, he was also born to mentoring. Stephanie Girard, recalls a moment early in her career, when David found her working in the Department Room. Noticing that she was tired, David “inquired, and when I told him that the girls in Dunbar were in my apartment almost every night asking for help,” he said,

“‘Stephanie, repeat after me: ‘No.’ . . . On days when you have too much of your own work to do, ask them when the test will be and see if they can wait a night or two. If it is the next day, say you can only work with them for half an hour. You must guard your own time carefully, so that this place does not wear you down.” Stephanie believes it “was great advice . . . given that I thought I was not allowed to turn the kids away regardless of my own workload or plans.” Close friend and colleague, Eric Bergofsky, says, “Add me to the list of those David mentored long before any formal mentoring program at Exeter was instituted.” David’s use of humor in the classroom continues to influence me “almost 50 years later. His legacy lives on.”

A life-long learner, David’s intellectual curiosity found joy in subjects as diverse as bird- watching and building fractals. For more than thirty years, March vacations provided time for David and Andra to birdwatch in Sanibel Island’s Ding Darling Wild Life Refuge and other nearby sanctuaries. David looked every inch the birder: Australian wide-brimmed hat, multi-pocketed vest, sunglasses, binoculars hanging by a strap around his neck, backpack, camera, and sturdy hiking boots. Rich Aaronian remembers a particularly pleasant trip with Peter Greer and David when they drove north to Canada’s Pelee National Park to see spring warblers returning from South America. Birdwatching is mostly, but not always a benign undertaking: Andra recalls one outing when David accidentally ventured too near the nest of a red-shouldered hawk. With screeching cries and talons flaring, the hawk plunged toward David’s head, sending his hat flying and leaving bloody scratches on his scalp.

Later in his career, David became fascinated with a pursuit that combined his mathematical skills with his artistic abilities: building fractals. Often beautiful and endlessly diverse, fractals are” infinitely complex patterns that repeat themselves at different scales.” Andy Hertig, who served as Dean of Faculty when David was the Director of Studies, frequently found “David’s computer screen filled with gradually developing colored patterns representing his newest fractal.” Andy recalls a moment when David’s cat “destroyed an entire night of fractal creation by walking across the keyboard of the computer in David’s living room.” Lost in that innocent moment of cat strolling was a particularly complicated model on which David had spent hours. With typical grace and good humor, David recounted the story to Andy. David loved his cat and understood that cats will be cats, eh?

Like many of his Exeter colleagues, David believed in the notion that to whom much is given, much will be required. For David, teaching in EMI was one way of giving back, a way of sharing Harkness pedagogy with colleagues across the country. Tony Greene and Bill Campbell recall being with David “on the same EMI team dozens of times.” Working together, Tony saw how much David “enjoyed teaching and how good he was at it. He and his teacher-students had fun, while at the same time he was boosting their confidence and imparting knowledge that would make them better teachers.” The EMI trips also enabled colleague Joe Wolfson to share in another of Dave’s passions: his love of fine food. Joe says, “We made it a point—just the two of us— to enjoy a dinner at a first-class restaurant one evening during our EMI week.” Joe treasures these moments of friendship, laughter, and lively conversation.

When David retired in 2006, the editors of the PEAN expressed their appreciation for David’s many contributions to the Exeter community: “Mr. Arnold has always pushed his students toward excellence. And his high standards are well-balanced by his playful humor and approachable nature. For his vivacious spirit, for his love of colorful shirts and bow ties, and for his talents as a teacher, mathematician, and advisor to all,” Mr. Arnold will be deeply missed.

On the 7th of April 2024, David Arnold passed into that good night. He is survived by his wife Andra Crawford and his son David Geoffrey Arnold.

With gratitude to several former colleagues for their contributions and the use of their words, we move that this Memorial Minute be submitted to David’s family and be spread upon the minutes of the faculty.

Respectfully submitted,

Richard S. Aaronian

Eric S. Bergofsky

William E. Campbell

Stephanie K. Girard

Anthony W. Greene

Richard A. Hardej

John D. Herney

Andrew W. Hertig

Lewis H. Hitzrot

Joyce C. Kemp

Joseph R. Wolfson

Douglas G. Rogers, Chair

This Memorial Minute was first published in the winter 2025 issue of The Exeter Bulletin.

Summer Morrill ’11 fell in love with studying biology and genetics while a student at Exeter. But it was her family history of breast cancer that inspired her to study genetics at Tufts, then in graduate school at MIT. “I’ve had the experience of meeting with a genetic counselor to try to understand what’s going on,” she says. “The things I’ve researched and discovered may not make a conscious impact during my lifetime, but there’s something empowering about studying it.”

While Morrill considered becoming a genetic counselor, she decided she was more suited to the academic side of science, especially after gaining teaching experience during graduate school. She teaches a course in cancer biology, BIO586: Molecular Genetics. She proposed it as a special course based on several students’ initial interest, but when she offered it, 25 students signed up. “So many students approached me asking for this course,” Morrill says.

Why so much interest? “Cancer research is a huge field with really interesting biology happening now,” she says. “Also, students personally are interested in learning more about cancer research. The disease touches a lot of families, friends and, at this point in their lives, they probably know someone who has cancer.”

Students in Morrill’s course read current research on cancer genetics and do lab work focused on learning techniques of DNA isolation, analysis and manipulation. Morrill also organizes a panel of biologists — representing organizations including Boston Children’s Hospital, the National Institutes of Health, and Merck — to meet students and answer questions. “The questions the students ask are what researchers are currently asking in the field, which is amazing,” she says.

Morrill is creating further iterations of the course, giving students more opportunities to tie together different elements they have learned, such as thinking how gene mutation works and what the human body can and can’t do in response. “If they understand a problem at multiple levels, that’s going to benefit their problem-solving ability when it comes to thinking about human disease and how we’re treating patients,” she says.

“A course like this can teach students that science is more than just memorizing a set of facts. It’s about being comfortable with the unknown and asking the right questions to further your understanding of the field. I think there’s huge value in that for students — even one who doesn’t want to go into cancer biology — to have the experience of connecting pieces together and doing research of your own to figure out what’s going on in such a new field.”

When my son was home from college recently, he mentioned the huge amount of information he is told on a daily basis. The learning feels different from his Exeter experience, he observed. He quickly realized that the greatest gift he received from Exeter was that Exeter taught him how to think.

It is an interesting point: Exeter’s math program focuses on creating problem solvers and deep thinkers. In traditional math classes, students are given problems in textbooks and told which methods they should employ to solve them. Exeter’s math students discover ideas on their own by working with one another through unique, interweaving problem sets.

Exeter math is taught, like the rest of our curriculum, in the Harkness tradition. Classes are student-centered. Teachers don’t lecture, we don’t feed students information. I view part of my role as a teacher as being responsible for creating a supportive classroom atmosphere where students are comfortable working with one another and they are unafraid to ask questions. We celebrate mistakes because mistakes create opportunities for learning and for increased collaboration. Growth and mastery emerge through students working together, actively exploring, discussing and explaining ideas to one another. We recently invited a film crew into my classroom to show how math at Exeter works. (You can watch the video of this class at Exeter’s YouTube channel.)

Our math problem sets are different too. Exeter’s dynamic, relevant problem sets (3,700 problems at last count!) keep mathematics interesting and realistic. The open-ended problems are scaffolded in a manner that enables students to work from specific examples to generalizations. Students develop concepts incrementally as they work through the theme-based recurring sequences of problems within our math sets. They dig into problems by searching for patterns, using technology, drawing diagrams, or whatever method seems appropriate to them.

Exeter math faculty began developing our problem sets in the 1990s. They are updated every June when current instructors review and revise the problems based on our own experience and with feedback from our students. The problems remain current and relevant. We are often asked why Exeter’s Math Department doesn’t publish our math problem sets as a book. The answer is easy: they are never finished.

Exeter math works. The way we introduce and scaffold our unique curriculum creates a gateway for developing fundamental problem-solving skills. Our technique moves students toward deeper thinking and stronger understanding that can lead to lifelong enjoyment of mathematical challenges.

Students don’t have to attend Exeter to benefit from our math program. We routinely partner with public, private and parochial school math teachers interested in thinking differently about math instruction. Our customizable Exeter Mathematics Institute fulfills an institutional priority to share the Harkness pedagogy with other educators while providing them with tools they can directly apply to their own curriculum. The end result, we hope, is inspired teachers who are committed to teaching students to gain independence in the learning process in order to become problem solvers. And ultimately, to provide the classroom environment that gives students, like my son, the space and confidence to be independent thinkers.

Learning advanced mathematics concepts isn’t necessarily fun and games — except in Instructor Jeff Ibbotson’s MAT690: Selected Topics in Mathematics course, where games are the point. In it, students explore how game theory — the study of strategic interactions whose outcome for each participant depends on choices of all involved — is an effective way to apply mathematical calculations to strategic thinking.

“Game theory allows students to see applications of mathematics in a different way because the concept is based on the idea of agents playing a game against one another or as part of a group,” Ibbotson says. “Games like the Prisoner’s Dilemma have aspects of conflict and cooperation, and can apply to situations in politics and economics.” Two of his students applied the game theory model of cooperation to show how hermit crabs trade shells, writing and illustrating a picture book to explain their findings.

Ibbotson aspires to teach mathematics beyond theorems and formulas, and attract a broad range of students, some who enjoy math and others who feel they should give math another try. Maybe because Ibbotson didn’t always know mathematics would be his route to happiness.

“When I was in college, I was a physics major and I wound up completing a physics program,” he says. “I took English classes, but eventually the style of arguments got to me. I was like I want something where there’s a provable answer. Not that I didn’t enjoy arguing, I do. … but it was when I was in real analysis that I fell in love with the mathematics of infinity.”

Drawing on his vast interests in art, religion and history, he uses spherical paintings on a globe to illustrate six-point perspective or passes around a graspable dodecahedron to help students visualize complex ideas. In another course he developed,

MAT40H: History of Mathematics, students study numbering systems from ancient Egypt, Babylon, China, India and other non-Western cultures — and have an opportunity to build their own. “They invent their own symbols and the stories behind the symbols,” Ibbotson says.

Ibbotson has been able to share his fondness for physics in an integrated studies course about the intersection of mathematics and sound. Using content based on his research into distribution theory and partial differential equations, students use trigonometric functions like sine and cosine to model complex sound waves (which correspond to musical concepts like pitch and volume). An avid Marvel and DC comic book fan, Ibbotson hasn’t integrated comics into his math courses, but he plans to.

In everything he teaches, Ibbotson strives to impart that learning mathematics is an effective way to learn to think, especially around the Harkness table. “That pedagogy feels right to me,” he says. “We want students engaged as soon as possible in doing mathematics. We have all sorts of problems that can go in various directions and sometimes the students find original ways to solve them. We celebrate that.”

Tara Lewis believes all students are artists, whether they have been sketching for years or have not picked up a paint brush since elementary school. A painter who often shows her work in New York City galleries, Lewis has taught painting, drawing, 3D design, printmaking and photography at all levels around a Harkness table in the Frederick R. Mayer Art Center. She draws on her dual passions in contemporary art (especially pop art) and portraiture to inspire students. “I love to weave the contemporary art world into my course content in a very impactful and tangible way,” she says.

Lewis regularly invites working artists to meet and work alongside students. American artist William Wegman visited campus to discuss the whimsical compositions he creates featuring dogs — mostly his Weimaraners in various costumes. Casey Cadwallader ’97, creative director for the fashion brand Mugler, made a guest appearance. Portrait artist Nicolas Coleman ’16 set up a mini studio in Lewis’s classroom and painted in tandem with students.

Some of these visits lead to further inspiration and connection. After hosting painter Will Cotton, several of Lewis’s former students went on to become studio assistants and interns. “The students gain technical inspiration that enhances their own studio practice,” Lewis says. “But it’s great when alumni come into the art classroom because I have them talk about what they were creating in high school or simply what they were like then. I want the students to realize that artists were actually 16 once too.”

Lewis enthusiastically shares personal experiences and insight in her ART408: Advanced Projects: Painting Portraits course. “My own studio practice is rooted in portraiture, and I love collaborations due to the unexpected and rewarding outcomes that can occur,” Lewis says. “I can’t help but let who I am spill into the classroom!” Early in the course, Lewis introduces possible portrait subjects through music videos, photography, literature, other artists’ work and more. Students develop a concept for the portrait they want to create, find a model, then create a portrait throughout the term.

Last spring in New York, a chance collaboration with model Brooke Shields led to an exhibition of Lewis’s pop culture-infused portraits of her and her daughters. She uses that example to motivate students.

“I love to share tips about the portrait process,” Lewis says. “I tell students to be present in the moment — know your concept, idea and subject you wish to portray. Make a documentary on canvas!”

Troy Samuels is known for making learning history a whole-body experience. Students in his HIS568: History Through Food course, for example, examine the relationship between cultures and food around the world through readings, then prepare a meal based on the concepts they’re discussing. “We have Harkness in the classroom, then we have Harkness in the kitchen,” Samuels says.

The course was inspired by a student project in one of Samuels’ 300-level European history classes. “A student from Venezuela researched the creation of Venezuelan food at the intersection of European and South American culture, which I thought was really cool,” Samuels says. “There are so many rich intersections between how food and the everyday lives of people interact with history.”

Based on themes provided by Samuels, each week two student “chefs” create a menu around a recipe they select and join Samuels in the basement of the Elizabeth Phillips Academy Center to cook a three-course meal. Exploring various themes such as food and economy, or food and empire, students prepare a variety of dishes — for example, lamb stew using ingredients adapted from a Babylonian cuneiform tablet or lobster rolls after discussing food and social status. They’re urged to taste everything (barring dietary restrictions or allergies). And, under Samuels’s supervision, they’re learning real cooking skills. “One of the broader trends we explore is how interconnected our world is,” he says. The class becomes a community event, especially on cooking days. “People invite their friends to help cook, to try things, to understand what they’re doing, and it becomes a little party,” he says.

In addition to cooking, Samuels encourages his students to engage with the active work of historians: digging. He is an archaeologist and a specialist in the material culture of understudied people in the ancient world. As a senior staff member on the Gabii Project, an international archaeological initiative in Italy, he has offered Exeter students the opportunity to work with him at the site outside Rome for the past two summers. “They’re the only high school students there, and they really distinguish themselves because they’re so insightful and energized,” Samuels says. “It’s also a great opportunity for them to experience a different side of being a historian.”

Samuels jokes that, “with a name like Troy, I was doomed to be an ancient historian,” but his hope is for students to find joy in learning history. “It’s about finding engagement with the past and that search for complexity and understanding and how that can be really rewarding,” he says.