The translucent blocks are made by mixing glass fibers into the combination of crushed stone, cement and water, varying a process that has been used for centuries to produce a versatile building material. The new process was devised by Hungarian architect Aron Losonczi in 2001.
http://seattletimes.nwsource.com/html/businesstechnology/2001974395_concrete08.html"Think of illuminating subway stations with daylight," he suggested in an e-mail. Or using the concrete for speed bumps and lighting them from below to make them more visible at night.