Porous surface used at Pentagon Memorial

While looking around the Internet for where to buy porous pavers, I stumbled across Invisible Structures, Inc, with this interesting article on one of their systems in use at the new Pentagon 9/11 memorial. They used a product called GravelPave2.

http://64.207.55.2/project_profile/browserecord.php?-lay=Form%20View&-action=browse&-recid=641

"The height of the Gravelpave2 and the Height of the pavers were matched. "
"The gravel surface is unique compared to many of the granite, marble, and concrete walking surfaces at memorials and monuments in Washington, D. C."
"To facilitate the use of gravel in the design, Kaseman and Beckman used Gravelpave2 to stabilize the loose aggregate and to allow for pedestrian, wheelchair, and stroller access."

The product description states:
"Gravelpave2 porous paving allows you to park, drive, walk, or ride on a beautiful decorative gravel surface."

This isn't what I'm looking for in my application, I'm probably going to go with open cell concrete block. Luckily I'm not a commercial business, because the current zoning and building codes in the City of Fredericksburg require parking lots to be paved. Anything else requires owners to submit for a special exception, or special use. In the most recent case, at least one council member voiced an opinion that perhaps the code needs to be updated to allow these new systems.