One striking element links the trio featured in Fleisher¹s current ³Challenge² exhibition: They honor art¹s most ancient sites -- walls. Aside from this -- and an overall satisfying quality of excellence -- the work of Michael Miller, Lori Spencer and Karen Stone has little in common. They, with nine others who have separate shows, were selected from a pool of 324 applicants in what is probably the area¹s most respected series of juried exhibitions. Fleisher¹s 25-year-old program is practically a rite of passage for Delaware Valley artists. Some, like Stone, are well-established before coming to the ³Challenge.²

The compulsive imprinting of many surfaces of prehistoric caves with hand silhouettes dovetails curiously, though probably unintentionally, with Stone's installation, Impact. Her patterning of walls, ceiling and floors with worn-out shoe soles is in other ways the most classic or traditional work in the show, reminding us how firmly installation art has established itself among accepted genres.

Stone is marvelously sensitive to the beauties and histories of human appurtenances. She opens our eyes to the grace of form and soft earthy colors of myriad pitifully eroded soles, each documenting infinite impacts of the human foot with solid surfaces. The shoe soles are organized along pathways, not mimicking the footprints of single individuals but suggesting rhythmic streams of traffic. Beneath the shoes, Stone covered all surfaces of the gallery in white. On the floor, ghostly prints of visitors' shoes make a whispering counterpoint in and around the real objects.

A squelching soundtrack of footsteps on a beach provides a continuous auditory context (for all three exhibitions). It begins to evoke some monstrous cosmic ruminant munching away -- ingesting and digesting -- all material substance in the course of time. Is there a deliberate punning relationship between soles and souls? Not necessarily. Words aren't needed to comprehend this surprisingly cheerful memento mori.

Michael Miller's two installations are examples of magic lens art. Not many practice it -- Richard Torchia is one -- but it's an identifiable school based on the wonder of vision illuminated by very refined technical means. Both Untitled #153 and Untitled #429 are composed of numerous small wall-mounted parallelepipeds, or angled corners of them. The earlier work, #153, utilizes magnifying lenses and mirrors to bounce light through the transparent sides of Masonite boxes. Some boxes contain lights. Others contain objects illuminated by reflections: a wishbone, stones, a tiny nest. In its details and in the aggregate, the arrangement is engaging and resolved.

Around 500 cement boxes in #429 process ambient light from spotlights through mirrors and clear glass. This work, more recent than #153, seems more passive and organic, but it's really more refined. Miller is in control, ever conscious of the grid but never a slave to it. Active scale shifts and subtle avenues of exploration defy complacency.

A feeling of cellular multiplicity suggests the aerial view of a village of small structures. Each houses mysterious and compelling life. Mirrors reflect us peering in, while photographic imagery visible inside the boxes is often architectural.

Lori Spencer's large ink-jet prints fill the two-dimensional surface and look like paintings, but their technology is relatively new. Spencer's decision to call them "drawings" is provocative. It acknowledges that in spite of rich layered color, they do not have the textural, physical density of paintings, but Spencer shies away from the label "print." Unlike photographic prints or intaglio, relief or screen prints, which all vary slightly one from another, ink-jet prints can be identical and reproduced an infinite number of times. On the other hand, Spencer's choice of "drawing" implies that each one is unique.

Within grid-based areas, hazy, painterly effects merge with delineated silhouettes, some recognizable as vegetation or human figures. Combining photographic sources with drawing and repeating motifs through the series, Spencer hints at a narrative which begins with Attainment and ends with Waiting. Or is it a cycle of endless permutations?

Through Feb. 8, Samuel S. Fleisher Art Memorial, 719 Catharine St., 215-922-3456