“Senility,” the great painter Agnes Martin (1912-2004) once wrote, “is looking back with nostalgia.”

Twenty-four of Martin’s works are currently on view in a show titled “Closing the Circle: Early and Late,” at PaceWildenstein. Fourteen are from the period 1957-65, while nine are from the last five years of her life, when, according to the gallery, she chose to “re-engage the geometric shapes and irregular grids that characterize” her early paintings.Although in her last works Martin looked back to the start of her career – one that really began in her mid-40s – her efforts suggest that even at 92, she was far from senile. Unlike so many artists in our backward-looking era, she didn’t have a whit of nostalgia in her.

But she did imbue her canvases with tremendous emotional energy: Her paintings, like the lines of her grids, often seem austere when first seen, but they vibrate with feeling when experienced at close hand and over time. Indeed, despite the fact that her work matured at roughly the same time as the Minimalist artists – a younger generation with which she is often grouped – she always insisted that her paintings were abstract and expressionist. It’s just that her expressivity was more hushed and less obviously heated than that of Jackson Pollock and Willem de Kooning.

Some emotion and expressiveness comes through in the few titles she gave to paintings (a practice, incidentally, that she engaged in only during the two periods treated here, early and late). In “Homage to Life” (2003), a black trapezoidal plane, like a single, bottomless font of possibility, seems to recede into to a mottled gray ground. It’s a work that appears to be related to a small, square untitled canvas from 1960 in which seven rectangular planes, stacked one atop another, float on a white ground.

“The Spring” (1958) looks a wee bit like a Mark Rothko, a contemporary who also showed with Martin’s first gallery, Betty Parsons. As with a number of her works, it is symmetrical top to bottom. A beige rectangular plane inside a white area is defined along its bottom edge by a gray line; another gray line divides the canvas in half; the bottom portion mirrors the top. Similarly, two groups of alternating pale yellow and pale aqua bands in the top portion of “Happiness” (2001-03) are mirrored by another set of 15 bands in the lower portion.

Were it not for the fact that Martin’s paintings utterly defy reproduction, she would probably be better known than she is today. A typical work unites thin, and often mottled, color washes – usually a mix of one or two colors plus white – with drawn graphite lines whose almost miniscule deviations from the straight edge erupt like seismic events. Hers is an art of delicate variation, of subtlety. The word “subtle” comes from the Latin subtilis, which means finely woven – it is no accident that the grids on which Martin’s work rings its changes so resemble the weaving patterns of the finest textiles.

The energy of her variations builds, like juice pumped into a battery, over time.The earliest work on view here,an untitled piece from 1957, consists simply of two large, vertically oriented rectangles, one yellow and one a somewhat grayer beige color, on a white ground.A small horizontal canvas from 1959 depicts four white rectangles summoned from the white background by the pencil lines that define them. The artist picks up the motif again nearly 50 years later, with “Untitled #14” (2002), in which a grayish plane is broken into eight rectangles by drawn graphite lines.

This play of motifs gives the show a sort of tidal feeling, a gentle back and forth between the distant and more recent past. One alcove, for instance, examines Martin’s use of triangles. And, looking, one is caught up in still another motion occurring with the works themselves: among the painting, the colors – where one normally finds the emotional core but which in Martin’s work tends to set a mood – and the drawing, the lines that map the expressive and emotional inner topography.

My favorite work on view, “The Sea” (2003) establishes a set of linear variations. Into a black square, the artist has scraped – probably using the handle of a brush – paired horizontal lines that run all the way to the white border, between which she has scraped four short horizontal lines.The whole makes for a notably woven-feeling pattern. On the left hangs a small untitled drawing, circa 1961, where the motif – long and short horizontal lines – was probably first thought through. On the right is another small work,a narrow,rectangular canvas painted black and laddered with horizontal lines drawn atop the pigment (rather than scraped in).

Martin, I’ve heard, was not a fan of circles, although there are two in one of the canvases here. Still, the circle is an apt figure for this exhibition, for it illustrates the fact that our beginnings are implicit in our ends, and vice versa. But what makes “Closing the Circle” such a wonderful show, aside from the magnificent works to be seen here, is how it mimics the ideal experience of Agnes Martin’s work: the back-and-forth motion between old and new paintings, as well as the back-and-forth tension between the elements within the works, between line and color, precision and wildness. It’s a motion that will rock you.

Until March 4 (32 E. 57th Street, between Fifth and Madison Avenues, 212-421-3292).