Then you fill the gaps of the paving with clear glass toughened beads, much like you would with rocks. But before you lay the beads down your run clear plastic garden hose lighting underneath the beads. You then wire the the hosing up to a beat sequencer for the different light runs, ie one around the perimetre, two or three times across the middle and as the beads are clear and the lighting hose has different colours your paving at night time would appear to beat in time with the music.

Easy way to turn your outdoor area into a groovy dance pad, garden lighting hose is readily available so water damage isn't a problem... and if you slid the hose into a c-section channel that faced down the light would still come out and you could slide the hose back in to replace globes etc.