Litracon is a really neat idea – concrete blocks reinforced with fiber optic cables. So light can pass through it. I was so impressed with this that I thought I would have a go at making some myself.
There was a neat Instructable recently that demonstrated one way to build it – I gave it try and got some very promising results. But I can think of a couple of improvements that would make the results even better.
The only real problem I had was that the fiber optic I used had a very pronounced bend in it – this meant that as the concrete cured some of the strands started to curl over and get buried in the concrete. If you try this, then use one of the fiber optic lamps available for under a tenner from target.com. These don’t suffer with the curling problem half as much.
Bill (our resident guru at work) pointed out that this is a very similar mechanism to Ulexite (http://en.wikipedia.org/wiki/Ulexite) which looks like a fascinating substance as well.