Or, you know, perspex. Hackers Curator has an interview with VFX supervisor Peter Chiang... who still has "The Gibson":

PC: We were very conscious of making the "Hacking" process visually exciting, not just lines of code, to allow the viewers who are not computer savvy to understand what is going on. We used all the available VFX processes, 2D, 3D, miniatures, matte paintings, motion control etc. to create the imagery.

HC: Perhaps this gave the ultimate leeway as many viewers wouldn't really be familiar with some of the concepts. What idea would was the hardest to flesh out regarding how to put imagery around an audience-unfamiliar concept?

PC: We loved the visual ideas of Muriel Cooper and wanted to represent moving through a 3D database. So we designed the data towers and represented them as full CG and also built physical miniatures made out of perspex. I still have one.

He also still has Zero Cool's laptop!

Previously, previously, previously, previously, previously, previously, previously, previously, previously, previously, previously.