Wayne Thiebaud, “Untitled (Three Ice Creams)” (1964), pastel and graphite, 9 1/4 x 12 1/4 inches (Private collection, image courtesy the Morgan Library & Museum, © Wayne Thiebaud/Licensed by VAGA, New York, NY)

Try to wedge Wayne Thiebaud’s work into any art historical category, and you’ll likely be left with crumbs. He’s not quite a Pop Artist, even though his iconic paintings of pies, ice cream cones, and hamburgers share similarities with the movement’s American food portraitists: Andy Warhol and Claes Oldenburg. And he’s not an Abstract Expressionist either, even though some of his brushstrokes are gestural and he befriended the movement’s greats (such as Willem de Kooning and Franz Kline).

Thiebaud’s paintings cannot be neatly classified or lumped under one header on the 20th-century art menu. But Wayne Thiebaud, Draftsman — an exhibition at New York’s Morgan Library & Museum and the first museum show to focus on the artist’s works on paper — lends a few helpful insights into who and what have inspired this 97-year-old artist (beyond the sugary obvious).

The answer, somewhat surprisingly, is a generous sprinkling of art history’s greats (and Thiebaud is willing to admit the influence, which many artists might prefer to leave mysteriously murky). As Isabelle Dervaux, Acquavella Galleries curator of Modern & Contemporary Drawings, notes in the show’s catalogue, Thiebaud was a self-motivated art student and increasingly followed the lead of his artistic predecessors as of the 1970s.

Wayne Thiebaud, “Shelf of Pies” (1960), brush and ink, watercolor, and charcoal (Private collection, photography by Graham S. Haber, image courtesy the Morgan Library & Museum, © Wayne Thiebaud/Licensed by VAGA, New York, NY)

Something shifted for Thiebaud when he painted his first pie painting. Hewanted to start fresh and focus on formal concerns of composition, shapes, and color. Many may look at his plated slices of pumpkin, blueberry, and apple pie and see triangles, but as of his very first painted slice (which Thiebaud claims was pumpkin) he saw them as a combination of the shapes that fascinated the Post-Impressionist painter Paul Cézanne.

“Cézanne remarks about basic units of painting: the cube, the cone, sphere,” Thiebaud explained in an artist talk at the Morgan Library & Museum in May. “I took [these] basic shapes to work with … Well, that’s a piece of pie.” Though pie surely has many other cultural associations, from a purely visual standpoint, Thiebaud was configuring the basic shapes that had preoccupied an artist considered to be the father of modern art.

Yet even after mastering the endless combinations of the cube, cone, and sphere in pie form, Thiebaud continued his repertoire of confections. As can be seen in Wayne Thiebaud, Draftsman, he often explored the same subject in multiple media, selecting techniques that emphasized either texture, color, or dramatic shadows. A pencil drawing captures the gritty crunchiness of a waffle cone; the saturated color and velvety quality of pastel are best suited for a dollop of ice cream; black ink brushwork shows the high-contrast shadows of jewel-toned candy apples on a white linoleum counter.

Wayne Thiebaud, “Candy Sticks” (1964), watercolor and graphite (Yale University Art Gallery, Bequest of Susan Morse Hilles, image courtesy the Morgan Library & Museum, © Wayne Thiebaud/Licensed by VAGA, New York, NY)

Despite his recurrent rows of pies and cakes, Thiebaud is not a pastry fanatic (or at least not any more than Cézanne had an apple fetish). “It’s a kind of research that painters use, called serialization,” Thiebaud explained at his artist talk. “Like Monet will paint eight haystacks, or Mondrian will make all these variations within a particular convention. So that’s what this is, really.”

In true form to his serializations, Thiebaud has absorbed other influences besides Cézanne. Going back to his pastels, he readily admits that he was inspired to use that medium by another artist. “I love pastels,” Thiebaud said enthusiastically to the audience at the Morgan Library & Museum. And in response to Dervaux’s follow-up question, asking what attracts him to it, he grinningly answered, “Degas.”

In the catalogue, Dervaux notes how Thiebaud is inspired by Edgar Degas’s dramatic compositions, in which an upturned empty floor dominates the canvas while other elements are pushed up against (or cut off by) the frame’s edges.

Degas’s paintings and drawings of people have been another inspiration — Thiebaud has a lesser-known interest in academic figure drawing (the type of 19th-century work on paper for which the Morgan is quite well known). Not only did it teach him how to look, but the difficulty of the process connected him with artists who had trained through that exercise before him. “If you keep making some marks, you sort of feel Degas has made those marks,” Thiebaud is quoted as saying in the catalogue. “And you’re making the same kind of marks, however inelegantly. But it’s the same sort of experience, and that’s, for me, very heartwarming.”

Wayne Thiebaud, “Toys” (1971), charcoal, from the artist’s studio (image courtesy the Morgan Library & Museum, © Wayne Thiebaud/Licensed by VAGA, New York, NY)

Sometimes Thiebaud literally made the same marks as his creative icons, making copies after other artists. (Thiebaud regularly instructs his drawing students to: “Copy pictures. Enjoy the hell out of it.”) One of these, exhibited in Wayne Thiebaud, Draftsman, is a copy of a Giorgio Morandi still life drawing. Thiebaud has reproduced it in its entirety, down to the signature.

But he also makes a note at the bottom of the drawing, informing viewers that it is a copy. “You want to be sure you’re not making a forgery,” Thiebaud explained at his artist talk at the Morgan. No one could accuse Thiebaud of forging the masters who served as his inspiration, since their influence is well hidden under the iced layers of sheet cake that pervade his canvases. But their traces are there, ever so subtle.

Wayne Thiebaud, Draftsman continues at the Morgan Library & Museum (225 Madison Avenue, Midtown East, Manhattan) closes on September 23.

Karen Chernick is a writer based in Philadelphia, by way of Tel Aviv. Her work has also appeared on Artsy, The Forward, Curbed Philadelphia, Eater, PhillyVoice, and Time Out Philadelphia.