A multicolored volleyball floats before your eyes. There is a hole in the ball big enough for your hand. You insert your fingers, feel for the edge.

But there is no edge.There is no ball.

There is only air and a remarkable three-dimensional illusion created through a process that leapfrogs laser technology and may fulfill some of holography's unkept promises.

The process is phscolography, (pronounced skoh-LAH'-grah-fee), a combination of photography, holography, sculpture and computer graphics.

Its inventors at the Illinois Institute of Technology and the University of Illinois at Chicago say phscolograms are easier and cheaper to create than laser-constructed holograms, a factor that could hasten the long-awaited advent of 3-D television.

They say phscolography's biggest advantage over holography is the ease with which it can transform computer-generated images into 3-D illusions. Most holograms are of physical objects.

"This thing can do impossible images," said Thomas DeFanti, a co-founder of UIC's Electronic Visualization Laboratory and a member of the artists-and-scientists collaborative that developed phscolography.

For example, the phscologram that resembled a blue, green, red and yellow volleyball was actually a computer-generated model of the polio virus. It is one of 47 phscolograms on display at Chicago's Museum of Science and Industry. The exhibit, titled "Science in Depth," runs through Jan. 13.

Among the exhibit's most intriguing pieces are eight phscolographic renderings of mathematical concepts. These are not numbers but bright abstract forms with titles like "Norton Fractal I" and "Strange Attractor" that essentially are computer-generated maps of how certain systems of mathematical equations behave.

"It's exciting to have a way for people to look at these visualizations," DeFanti said.

He said that by looking at a 3-D visualization of an abstract concept, scientists can sometimes make connections they would otherwise have missed.

The museum's works also include 3-D architectural photos, visualizations of various molecules and a cross-shaped montage of images - tumbling dice, human head and hands, and an AIDS virus - meant to suggest the roles of hope and chance in finding a cure for the deadly disease.

"We're marrying art, science and math," said sculptor Ellen Sandor, a leader in phscolography research since 1983.

Three-dimensional imaging goes back to the early days of photography but got a big boost in the 1960s when lasers first were used to construct holograms. Some scientists predicted that holographic home entertainment centers would become common by the year 2000.

Phscolograms resemble holograms but have more in common with 3-D postcards.