But if the convergences of accident and purpose, impulse and routine, characterize the Cunningham stage, what happens when only a single dancer occupies it, as in the starriest, most labor-intensive event of the choreographer’s centenary? On his birthday proper, this Tuesday April 16, a decade since he died at age 90, “Night of 100 Solos” will take place at BAM in New York, the Barbican in London, and the Center for the Art of Performance at the University of California Los Angeles. All told, 75 superlative dancers pointedly outside the Cunningham fold will take up solos scattered across six decades of his work. Sometimes several solos will unfold together, sometimes one at a time. In the latter case, will it be like watching either Icarus plunge into the water or the ploughman and his horse? Does it mean choosing between mundanity and tragedy, banality and the sublime?

I went to the first weekend of the 92^nd Street Y’s Harkness Dance Festival last month to find out. Dedicated to Cunningham and his progeny, the 25^th anniversary season began with the man himself, including solos performed by Melissa Toogood. A member of his troupe from 2007 to its finale on the eve of 2012, Toogood would indeed be too good if the choreography didn’t require such exorbitant excellence.

Her two solos spanned as many decades, from 1984 (“Doubles”) to 2002 (“Loose Time”). The arms are always first to give away the difference. Before severe arthritis reduced him to a wheelchair, Cunningham invented steps for a purely human frame. The resting position of these early arms curve like parentheses around the volatile torso and steady thighs. In 1989 the choreographer was introduced to the software Life Forms (and it to him. His play with this sophisticated and flexible movement generator, now known as DanceForms, aided in its evolution.) If every move is valid, why not the software’s stiff imitation of the human skeleton? Cunningham embraced computer mind with the same Zen glee he reserved for all contingencies. Soon the arms resembled shelf brackets, a shape they maintained even as the torso swiveled, as if ball and socket were soldered tight. Besides the shape of arms, the other striking development was an exponential increase in the steps’ complication and density.

Surprise, however, has been a constant. “There are no new steps,” Balanchine once said, “only new combinations.” By submitting the joinery—the transitions—to chance operations, Cunningham guaranteed that novelty. And unlike Balanchine, no notions of God or fate intruded on possibility. Cunningham dancers roam a terrain that in part they seem to have shaped and in part merely to inhabit. The Cunningham drama lies in that ambiguous distinction, ever drawn and redrawn, in pencil.

In the 1984 “Doubles” solo, the Cunningham steps were in such unanticipated order that even minutes later I could only remember the typical moves: the circumferencing ronds de jambes en l’air, followed by a sudden crook of leg and crumple of torso; the birdlike scatter; the triplets. And in my ambition to record the details—and my inability to choose between them—my scribbles in the dark proved useless. At least the spirit of the piece remained clear, as did the moment when Toogood knelt in profile far downstage and rotated her torso towards us, retracting her arm as if to shoot an arrow or open a cabinet (I can’t remember which). The Faunesque frieze—a dance-historical allusion!—and the rare instance of floorwork transformed kinesthetic sensation into image.

That image acts like a fragile carapace around the choreography’s constant life. Too thick a shell distances us. At the Y, the New York Theatre Ballet’s valiant forays into early Cunningham—the sextet “Septet” (1953) and the trio “Cross Currents” (1964)— suffered from this shapeyness. Too weak an imprint, and the steps seem a mere excuse for thrashing about. Toogood found the perfect mean. For the “Doubles” solo, you experienced an oddly steadying excitement as she made the decision to begin, to end, to dwell, to curtail, to leave or stay. She realized these essential aims with animal suddenness, not human rashness or whimsy—which is to say, with unknown intent. The choreography rarely repeated the form her choices took, yet each beginning and end functioned like the breadcrumbs in the Hansel and Gretel tale. They kept us from getting lost.

In the second solo—the famously impossible bit from “Loose Time” that Cunningham made for the unflappable, pellucid Holley Farmer in 2002—Toogood stretched an arm down her torso toward the floor, her hand like a spade sinking up to its handle in loam. The phrase faded at its edges like light into darkness. Cunningham steps often accelerate and decelerate without warning. They appeal to Dada more than physics. Unlike ballet or release technique, to consider polar opposites, they don’t take much advantage of centrifugal force, gravity or momentum. Dancers must inhibit habit, as students from Miami’s New World School for the Arts surely discovered with the MinEvent (a half-hour mashup of repertory works) that Toogood staged for them for this 92Y outing. Splendid moments abounded, but they didn’t involve cracking open the phrases to release their eccentric secrets.

Which might be cause for worry over this upcoming night of solos by Cunningham novitiates if not for the splendid example of Calvin Royal III, who joined Toogood for duets. The long- and loose-limbed American Ballet Theatre soloist is more often circumspect and regal than creaturely and quixotic, yet it hardly matters what he usually is. To dance Cunningham is to embrace whatever you assume is unlike yourself. Royal’s advantage is that he has created roles for ABT’s resident choreographer, Alexei Ratmansky, who also stretches dancers beyond their imaginings—and often in two directions at once, the legs like rapiers while the innocent torso bends and flops.

For duets from “Scenario” (1997) and “Trails” (1982) as well as the “Merce solo” from “Landrover”(1972), Royal had clearly absorbed Toogood’s M.O.—her bright attack and the grainy rhythm she massages into long phrases to roughen and tighten them up. He added an easy play of head and hip all his own that seemed, however, always to have been there, just waiting for him to come along and notice.

The pair understood that as long as they attended to beginnings and endings—which includes deciding when the phrase begins and ends—the rest would follow. The hand-clasps at one point in “Scenario” counted as such a mark. Royal and Toogood used their grip as ballast—he to barrel turn and she to arch or curve her back, head to knee. Just before, he would turn away and lunge, stretching an arm back for her to grab, or turn to face her and stretch the arm forward. Each move had its own beat. There was no blur between moves or people, no overlap except in the hands.

“Put a man and a girl on the stage, and there is already a story,” Balanchine said, perhaps in response to a complaint about his ballets’ lack of plot. The story he had in mind was romance. Though we catch the charge between Royal and Toogood as he blindly stretches back his hand and she answers by flexing her spine, the story doesn’t already exist. It emerges in the split second of deliberation before they take each other’s hand. It evolves with each subsequent hand-clasp. The dancers have decided to do the seemingly natural thing—with each reiteration making it more natural.

The solos concentrate these expressions of intent—the dense, late solos especially. In “Loose Time,” an aleatory symphony plays across Toogood, as if half the torso were legato cello, the other half allegro flute, and the figure-eight of a lower leg a 6/8 chorus of violins. The actual music for this occasion is borrowed from the “Doubles”score, by Takehisa Kosugi, the music director who succeeded John Cage. Kosugi’s “Spacings” sounds like a goofball space alien’s notion of a twittering bird orbiting a tiny planet: the perfect musical corollary to a dance that teeters between human and machine.

You would think that the more cutup the body and phrasing, the more the dancer’s choices would diminish—that it’s as much as a dancer can do to get through the assignment. But Toogood does not have the luxury of relinquishing choice. She does not have Farmer’s hyper-flexible hips to help make a machine of herself. With Farmer, the joints took the lead as they ground and turned in their sockets. Toogood substitutes momentum wherever she can. She brings a loose pixie quality to the thorny steps. She is a creature enlisting whimsy to emulate a machine.

A Cunningham solo brings out the dancer’s innumerable executive decisions. To return to Bruegel, it is not just a matter of how the ship ploughs the sea and the farmer manoeuvers the horse and the eager boy descends—all these actions at once. There are also implicit details to flesh out or not. Does the ploughman hear the fatal splash? Does the boy cry out before he drowns? The dancer decides.