Tony Cragg’s new sculptures are very difficult to describe, which by their own criteria is a measure of success. These are sculptures in the mold of Shakespeare’s phrase “the forms of things unknown.” They convey, at once, the sense of being rock-solid and in a radical state of flux. They have vaguely familiar features, and yet they are impossible to place even to the broadest of categories: animal, vegetable, mineral.

Viewed from one angle, at least, “Caught Dreaming” (2006) could read as some sort of prehistoric bison, or a postapocalyptic mutation of one. It rests on two points that could register as pairs of legs, it has a hump, and two flopping, irregular shapes could pass at a pinch as ears. Its body is a mass of Michelin Man-like folds.

“Mental Landscape” (2007) has similarly limblike components that assume a quadruped posture, but it could equally be a floating rock formation from a Chinese scroll painting.

But then, catching the already disconcerted viewer offguard, there are human facial features that emerge amid the stretched loops and weird folds. In “Caught Dreaming,” there are intimations of faces, with ears sticking out at the edges. It is as if the body has been caught in a fantastically distorted funfair mirror that leaves only the outermost extremity legible — barely. In “Mental Landscape,” the faces are bigger, though just as slow to emerge. Here, a succession of faces reads like a kind of sci-fi Mount Rushmore.

The enigma begins to resolve as it becomes likely that these sculptural forms are the result of computer generated distortions of photographic sources, and that the inexplicable shape and surface might have been lasercut, electronically guided. But even as mysteries of facture and image source recede, the sheer oddity of these sculptures remains.

Marian Goodman’s extensive galleries are filled with 16 new works, each generally around 10 feet in outer extremity. Though there is a consistency of form vocabulary, there is a plethora of materials and surface (one for each work): polished bronze, compacted wood, painted bronze, textured bronze, stainless steel, and a material called diabase (it looks manmade though is a natural substance). Bizarre though the forms are, they are also formally rather beautiful in their voluptuous finesse and sinuous sensuality. They are also glorious fun.

Some of the pieces recall Mr. Cragg’s earlier vocabulary of science lab vessels: “Outspan” (2007), for instance, a piece in yellow painted bronze that sits in a smaller viewing room with works in polished bronze and red painted bronze. It is still hard to verbalize what is happening or how it looks, but there is a sense of a hollow form whose lips are distorted in parallel.

Mr. Cragg’s sculpture has come a long way since he emerged in Britain in the late 1970s as a late disciple of Arte Povera, working with recycled materials and appropriated objects. He can be said to have gone from one extreme to another, from the found and simple to the manufactured and complex. But there is also considerable unity in his enterprise: His work has always been visually arresting and philosophically challenging.

As much as any he has produced, this new work reflects his personal career path: He had worked as a laboratory technician for the National Rubber Producers Association before going to art school: His work is technically complex, impersonal in touch, and methodical in the way each explores a different aspect of a similar problem. But Mr. Cragg is not merely an exporter of the lab aesthetic to the art world. Though his stated ambition is to generate works “without using preconceived notions of an already occupied language,” his works relate to the history of sculpture. Their dynamism and flux relates to Umberto Boccioni’s Futurist sculpture “Unique Forms of Continuity” (1913). Mr. Cragg’s creations also exude a strong romantic sensibility, exploring metamorphosis in a way that looks to Hans Arp and Henry Moore. You could say Mr. Cragg’s is a biomorphism with edge.

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Further west on 57th Street, Don Gummer also works with rules and systems to force the static to suggest flow and the rigid to yield unexpected perspectives. But viewing him after Mr. Cragg is to change from stilettos to sensible shoes. Mr. Gummer is a strong, solid modernist whose sober works drip feed sculptural felicities rather than inundate with them.

His latest group of wall-mounted structures exploits a simple idea and sees it through with grace. He has made models of ground plans of canonical works of architecture in hand-painted strips of wood, combining two or three in each piece. “Fallingwater Over Broadacre” (2006), for instance, attaches skeletal, unornamented models of these two Frank Lloyd Wright residences, one over the other, Broadacre in gray and Fallingwater in maroon. Each model is itself a rectangle of 5 inches in height (height from the architectural perspective, that is; depth when wallmounted). The paint is loosely applied and the models are finely crafted but clearly handmade, giving them a tenderness that belies their schematics.

Other couplings include a pair of Italian churches, one Renaissance, the other Medieval; and a contemporary Japanese studio over R.M. Schindler’s Packard Residence in Los Angeles. There is an interesting overlap of concerns here with Rebecca Smith’s recent show of wall-mounted metal pieces that followed the contours of glaciers — an overlap reinforced by the fact that Ms. Smith’s dealer, Laurie Fendrich, is the author of Mr. Gummer’s catalog essay.

Freestanding works include “Outside the Rules” (2007), which is subversive, at least by Mr. Gummer’s standards, in its placement of off-kilter, patinated steel houselike structures within a wavy column of open-lattice stainless steel, and a pair of constructivist assemblages in bronze, “Astaldi II and III” (both 2006), whose simplified, primitive feel harks back to early modernism.

Cragg until June 9 (24 W. 57th St., between Fifth and Sixth avenues, 212-977-7160);

Gummer until June 5 (40 W. 57th St., between Fifth and Sixth avenues, 212-541-4900).